Causal analysis of serum polyunsaturated fatty acids with juvenile idiopathic arthritis and ocular comorbidity.

BACKGROUND & OBJECTIVE: To investigate the causal effects of plasma Polyunsaturated fatty acids (PUFAs) on the risk of juvenile idiopathic arthritis (JIA) and ocular comorbidity through Mendelian randomization (MR) analysis. METHODS: Genetic variants (formerly single nucleotide polymorphisms, SNPs) that are strongly associated with PUFAs levels (P < 5×10-8) were selected as instrumental variables. Summary-level MR was performed with outcome estimates for JIA (n = 31,142) and JIA associated iridocyclitis (n = 94,197). The inverse variance-weighted (IVW) method was employed as the main approach to combine the estimation for each SNP. Two set of models with summary statistics were conducted and multiple sensitivity analyses were applied for testing of pleiotropic bias. RESULTS: In model 1, genetically predicted n-6 PUFAs linoleic acid (LA) and arachidonic acid (AA) were associated with lower and higher risk of JIA associated iridocyclitis using IVW (ORLA = 0.940, 95% CI: 0.895-0.988, P = 0.015; ORAA = 1.053, 95% CI: 1.007-1.101, P = 0.024). No such association was observed between each plasma PUFAs and JIA susceptibility (P > 0.05). In further MR analysis, results from model 2 also showed a consistent trend. Besides, multiple sensitivity analyses revealed that there was no obvious evidence for unknown pleiotropy (P > 0.05). CONCLUSIONS: Our MR study provides genetic evidence on the possible causality that plasma LA level might protect against JIA associated iridocyclitis, whereas AA was responsible for opposite effect.

Causal Effects of N-6 Polyunsaturated Fatty Acids on Age-related Macular Degeneration: A Mendelian Randomization Study.

CONTEXT: Although the role of n-6 polyunsaturated fatty acids (PUFAs) in age-related macular degeneration (AMD) has been studied in previous observational studies, the precise manner in which 1 or more n-6 PUFAs account for this relationship remains unclear. OBJECTIVE: Using genetic instruments for n-6 PUFAs traits implemented through mendelian randomization (MR), we aimed to study possible causal associations between n-6 PUFAs and AMD. METHODS: The 2-sample MR method was used to obtain unconfounded causal estimates. We selected genetic variants strongly associated (P < 5 × 10-8) with circulating linoleic acid (LA) and arachidonic acid (AA) from a study involving 8 631 individuals and applied to an AMD case-control study (33 526 participants and 16 144 cases). The weighted median and MR Egger methods were used for the sensitivity analysis. RESULTS: Our MR analysis suggested that circulating LA was a causal protective factor for AMD, with an odds ratio (OR) estimate of 0.967 (95% CI 0.945 to 0.990; P = .005) per percentage in total fatty acid increase in LA. In contrast, higher genetically predicted circulating AA causally increased the AMD risk (OR = 1.034; 95% CI 1.012 to 1.056; P = .002). Sensitivity analysis provided no indication of unknown pleiotropy. The findings from different single-nucleotide polymorphism selections and analytic methods were consistent, suggesting the robustness of the causal associations. CONCLUSION: Our study provided genetic evidence that circulating LA accounted for protective effects of n-6 PUFAs against the risk of AMD, whereas AA was responsible for deleterious effects on higher AMD risk.

Eicosanoid Signaling in Insect Immunology: New Genes and Unresolved Issues.

This paper is focused on eicosanoid signaling in insect immunology. We begin with eicosanoid biosynthesis through the actions of phospholipase A2, responsible for hydrolyzing the C18 polyunsaturated fatty acid, linoleic acid (18:2n-6), from cellular phospholipids, which is subsequently converted into arachidonic acid (AA; 20:4n-6) via elongases and desaturases. The synthesized AA is then oxygenated into one of three groups of eicosanoids, prostaglandins (PGs), epoxyeicosatrienoic acids (EETs) and lipoxygenase products. We mark the distinction between mammalian cyclooxygenases and insect peroxynectins, both of which convert AA into PGs. One PG, PGI2 (also called prostacyclin), is newly discovered in insects, as a negative regulator of immune reactions and a positive signal in juvenile development. Two new elements of insect PG biology are a PG dehydrogenase and a PG reductase, both of which enact necessary PG catabolism. EETs, which are produced from AA via cytochrome P450s, also act in immune signaling, acting as pro-inflammatory signals. Eicosanoids signal a wide range of cellular immune reactions to infections, invasions and wounding, including nodulation, cell spreading, hemocyte migration and releasing prophenoloxidase from oenocytoids, a class of lepidopteran hemocytes. We briefly review the relatively scant knowledge on insect PG receptors and note PGs also act in gut immunity and in humoral immunity. Detailed new information on PG actions in mosquito immunity against the malarial agent, Plasmodium berghei, has recently emerged and we treat this exciting new work. The new findings on eicosanoid actions in insect immunity have emerged from a very broad range of research at the genetic, cellular and organismal levels, all taking place at the international level.

Research advances on arachidonic acid production by fermentation and genetic modification of Mortierella alpina.

Arachidonic acid (ARA, 5, 8, 11, 14-cis-eicosatetraenoic acid) is a relevant ω-6 polyunsaturated fatty acid, which plays essential roles in human immune, cardiovascular, and nervous systems. It is widely used in medicine, cosmetics, nutrition, and other fields. Traditionally, ARA is obtained from animal tissues. However, due to the limitation and unsustainability of existing resources, microorganisms are a potential alternative resource for ARA production. In this regard, major efforts have been made on algae and filamentous fungi, among which Mortierella alpina is the most effective strain for industrial ARA production. In this review, we summarized the recent progress in enhancing M. alpina production by optimization of culture medium and fermentation process and genetic modification. In addition, we provided perspectives in synthetic biology methods and technologies to further increase ARA production.

Genetically predicted plasma phospholipid arachidonic acid concentrations and 10 site-specific cancers in UK biobank and genetic consortia participants: A mendelian randomization study.

BACKGROUND & AIMS: Arachidonic acid (AA) is metabolized by cyclooxygenases and lipoxygenases to pro-inflammatory eicosanoids, which according to experimental research modulate tumor cell proliferation, differentiation, and apoptosis. We employed the Mendelian randomization design to test the hypothesis that higher plasma phospholipid AA concentrations are associated with increased risk of 10 site-specific cancers. METHODS: Two genetic variants associated with plasma phospholipid concentrations of AA (rs174547 in FADS1 [P = 3.0 × 10-971] and rs16966952 in PDXDC1 [P = 2.4 × 10-10]) in the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium were used as genetic instruments. The associations of those variants with cancer were taken from the UK Biobank (n = 367,643), FinnGen consortium (n = 135,638), International Lung Cancer Consortium (n = 27,209), Prostate Cancer Association Group to Investigate Cancer Associated Alterations in the Genome consortium (n = 140,254), Breast Cancer Association Consortium (n = 228,951), Ovarian Cancer Association Consortium (n = 66,450), and BioBank Japan (n = 212,453). RESULTS: Higher genetically predicted plasma phospholipid AA concentrations were associated with increased risk of colorectal and lung cancer. Results were consistent across data sources and variants. The combined odds ratios per standard deviation increase of AA concentrations were 1.08 (95% CI 1.05-1.11; P = 6.3 × 10-8) for colorectal cancer and 1.07 (95%CI 1.05-1.10; P = 3.5 × 10-7) for lung cancer. Genetically predicted AA concentrations had a suggestive positive association with esophageal cancer (odds ratio 1.09; 95% CI 1.02-1.17; P = 0.016) but were not associated with cancers of the stomach, pancreas, bladder, prostate, breast, uterus, or ovary. CONCLUSION: These results indicate that AA may be implicated in the development of colorectal and lung cancer and possibly esophageal cancer. Treatments with plasma AA-lowering properties should be evaluated for clinical benefit.

Regulation and role of Acyl-CoA synthetase 4 in glial cells.

Acyl-CoA synthetase 4 (Acsl4), an enzyme involved in arachidonic acid (AA) metabolism, participates in physiological and pathological processes such as steroidogenesis and cancer. The role of Acsl4 in neurons and in nervous system development has also been documented but little is known regarding its functionality in glial cells. In turn, several processes in glial cells, including neurosteroidogenesis, stellation and AA uptake, are regulated by cyclic adenosine monophosphate (cAMP) signal. In this context, the aim of this work was to analyze the expression and functional role of Acsl4 in primary rat astrocyte cultures and in the C6 glioma cell line by chemical inhibition and stable silencing, respectively. Results show that Acsl4 expression was regulated by cAMP in both models and that cAMP stimulation of steroidogenic acute regulatory protein mRNA levels was reduced by Acsl4 inhibition or silencing. Also, Acsl4 inhibition reduced progesterone synthesis stimulated by cAMP and also affected cAMP-induced astrocyte stellation, decreasing process elongation and increasing branching complexity. Similar effects were observed for Acsl4 silencing on cAMP-induced C6 cell morphological shift. Moreover, Acsl4 inhibition and silencing reduced proliferation and migration of both cell types. Acsl4 silencing in C6 cells reduced the capacity for colony proliferation and neurosphere formation, the latter ability also being abolished by Acsl4 inhibition. In sum, this work presents novel evidence of Acsl4 involvement in neurosteroidogenesis and the morphological changes of glial cells promoted by cAMP. Furthermore, Acsl4 participates in migration and proliferation, also affecting cell self-renewal. Altogether, these findings provide insights into Acsl4 functions in glial cells.

Molecular determinant of substrate binding and specificity of cytochrome P450 2J2.

Cytochrome P450 2J2 (CYP2J2) is responsible for the epoxidation of endogenous arachidonic acid, and is involved in the metabolism of exogenous drugs. To date, no crystal structure of CYP2J2 is available, and the proposed structural basis for the substrate recognition and specificity in CYP2J2 varies with the structural models developed using different computational protocols. In this study, we developed a new structural model of CYP2J2, and explored its sensitivity to substrate binding by molecular dynamics simulations of the interactions with chemically similar fluorescent probes. Our results showed that the induced-fit binding of these probes led to the preferred active poses ready for the catalysis by CYP2J2. Divergent conformational dynamics of CYP2J2 due to the binding of each probe were observed. However, a stable hydrophobic clamp composed of residues I127, F310, A311, V380, and I487 was identified to restrict any substrate access to the active site of CYP2J2. Molecular docking of a series of compounds including amiodarone, astemizole, danazol, ebastine, ketoconazole, terfenadine, terfenadone, and arachidonic acid to CYP2J2 confirmed the role of those residues in determining substrate binding and specificity of CYP2J2. In addition to the flexibility of CYP2J2, the present work also identified other factors such as electrostatic potential in the vicinity of the active site, and substrate strain energy and property that have implications for the interpretation of CYP2J2 metabolism.

Polyunsaturated fatty acid biosynthesis pathway determines ferroptosis sensitivity in gastric cancer.

Ferroptosis is an iron-dependent regulated necrosis mediated by lipid peroxidation. Cancer cells survive under metabolic stress conditions by altering lipid metabolism, which may alter their sensitivity to ferroptosis. However, the association between lipid metabolism and ferroptosis is not completely understood. In this study, we found that the expression of elongation of very long-chain fatty acid protein 5 (ELOVL5) and fatty acid desaturase 1 (FADS1) is up-regulated in mesenchymal-type gastric cancer cells (GCs), leading to ferroptosis sensitization. In contrast, these enzymes are silenced by DNA methylation in intestinal-type GCs, rendering cells resistant to ferroptosis. Lipid profiling and isotope tracing analyses revealed that intestinal-type GCs are unable to generate arachidonic acid (AA) and adrenic acid (AdA) from linoleic acid. AA supplementation of intestinal-type GCs restores their sensitivity to ferroptosis. Based on these data, the polyunsaturated fatty acid (PUFA) biosynthesis pathway plays an essential role in ferroptosis; thus, this pathway potentially represents a marker for predicting the efficacy of ferroptosis-mediated cancer therapy.

Chronic ethanol consumption and HBV induce abnormal lipid metabolism through HBx/SWELL1/arachidonic acid signaling and activate Tregs in HBV-Tg mice.

Rationale: Chronic ethanol consumption as a public health problem worldwide boosts the development of chronic liver diseases in hepatitis B virus (HBV)-infected patients. Arachidonic acid metabolite prostaglandin E2 (PGE2) activates regulatory T cells (Tregs) function. Here, we aim to investigate the underlying mechanism by which chronic ethanol consumption enriches the HBV-induced abnormal lipid metabolism and Tregs. Methods: The si-RNAs were used to weaken the expression of SWELL1 in HepG2, HepG2.2.15 and K180 cancer cell lines, followed by RNA sequencing from HepG2 cells. Arachidonic acid metabolite PGE2 and LTD4 were measured by ELISA assay in vivo and in vitro. Western blot analysis and RT-qPCR were used to examine HBx and SWELL1 and transcriptional factor Sp1 in clinical HCC samples and cell lines. The effect of chronic ethanol consumption on Tregs was tested by flow cytometry in HBV-Tg mice. The splenic Tregs were collected and analyzed by RNA sequencing. Results: The cooperative effect of ethanol and HBV in abnormal lipid metabolism was observed in vivo and in vitro. The depression of SWELL1 (or HBx) resulted in the reduction of lipid content and arachidonic acid metabolite, correlating with suppression of relative gene atlas. Ethanol and SWELL1 elevated the levels of PGE2 or LTD4 in the liver of mice and cell lines. Interestingly, the ethanol modulated abnormal lipid metabolism through activating HBx/Sp1/SWELL1/arachidonic acid signaling. Chronic ethanol consumption remarkably increased the population of PBL Tregs and splenic Tregs in HBV-Tg mice, consistently with the enhanced expression of PD-L1 in vivo and in vitro. Mechanically, RNA-seq data showed that multiple genes were altered in the transcriptomic atlas of Tregs sorting from ethanol-fed mice or HBV-Tg mice. Conclusion: The chronic ethanol intake enriches the HBV-enhanced abnormal lipid metabolism through HBx/SWELL1/arachidonic acid signaling and activates Tregs in mice.

Systematic genome analysis of a novel arachidonic acid-producing strain uncovered unique metabolic traits in the production of acetyl-CoA-derived products in Mortierellale fungi.

The fungi in order Mortierellales are attractive producers for long-chain polyunsaturated fatty acids (PUFAs). Here, the genome sequencing and assembly of a novel strain of Mortierella sp. BCC40632 were done, yielding 65 contigs spanning of 49,964,116 total bases with predicted 12,149 protein-coding genes. We focused on the acetyl-CoA in relevant to its derived metabolic pathways for biosynthesis of macromolecules with biological functions, including PUFAs, eicosanoids and carotenoids. By comparative genome analysis between Mortierellales and Mucorales, the signature genetic characteristics of the arachidonic acid-producing strains, including Δ5-desaturase and GLELO-like elongase, were also identified in the strain BCC40632. Remarkably, this fungal strain contained only n-6 pathway of PUFA biosynthesis due to the absence of Δ15-desaturase or ω3-desaturase gene in contrast to other Mortierella species. Four putative enzyme sequences in the eicosanoid biosynthetic pathways were identified in the strain BCC40632 and others Mortierellale fungi, but were not detected in the Mucorales. Another unique metabolic trait of the Mortierellales was the inability in carotenoid synthesis as a result of the lack of phytoene synthase and phytoene desaturase genes. The findings provide a perspective in strain optimization for production of tailored-made products with industrial applications.

Inhibition of CYP1B1 ameliorates cardiac hypertrophy induced by uremic toxin.

Cardiovascular disease is the predominant complication and leading cause of mortality in patients with chronic kidney disease (CKD). Previous studies have revealed that uremic toxins, including indoxyl sulfate (IS), participate in cardiac hypertrophy. As a heme­thiolate monooxygenase, cytochrome P450 family 1 subfamily B member 1 (CYP1B1) is able to metabolize arachidonic acid into hydroxyeicosatetraenoic acids, which are thought to serve a central function in the pathophysiology of the cardiovascular system. However, whether CYP1B1 is involved in cardiac hypertrophy induced by uremic toxins remains unknown. The present study revealed that the expression of the CYP1B1 gene was significantly (P<0.05, CKD or IS vs. control) upregulated by CKD serum or IS at the transcriptional and translational level. Furthermore, IS treatment resulted in the nuclear translocation of aryl hydrocarbon receptor (AhR), an endogenous ligand of IS. Binding of AhR in the promoter region of CYP1B1 was confirmed using a chromatin immunoprecipitation assay in the cardiomyoblast H9c2 cell line. In addition, knockdown of AhR or CYP1B1 reversed the production of cardiac hypertrophy markers. The in vivo injection of a CYP1B1 inhibitor significantly (P<0.05, Inhibitor vs. control) attenuated cardiac hypertrophy in mice. The data from the present study clearly demonstrated that CYP1B1 was involved in cardiac hypertrophy induced by uremic toxins.

Expression of Cytosolic Phospholipase A2 (cPLA2)-Arachidonic Acid (AA)-Cyclooxygenase-2 (COX-2) Pathway Factors in Lung Cancer Patients and Its Implication in Lung Cancer Early Detection and Prognosis.

BACKGROUND The aim of this study was to elucidate the involvement of cPLA2-AA-COX-2 pathway factors and their potential role in lung cancer early diagnosis and prognosis. MATERIAL AND METHODS We selected 80 lung cancer patients as the cancer group, and 30 normal patients were selected as the normal group. Serum contents of COX-2, cPLA2, COX-1, mPGES, PGE2, and PGI2 were measured, and mRNA levels of COX-2, cPLA2, COX-1, and mPGES in serum were determined. Spearman's P-test was used to analyze the correlation between expression of PGI2 and mPGES in serum and the clinical characteristics of these lung cancer patients. The factors affecting the prognosis lung cancer were analyzed by COX regression model. RESULTS The serum contents of COX-2, cPLA2, COX-1, mPGES, PGE2, and PGI2 in the cancer patient group were significantly higher (p<0.05) than in the normal group; after treatment, the serum contents of these factors were significantly decreased (p<0.05). However, distant metastasis had a significant effect on serum contents of mPGES and PGI2 (p<0.05), but not on the other factors. The mRNA levels of COX-2, cPLA2, COX-1, and mPGES in cancer patients were significantly higher than in normal patients. In addition, the 5-year survival rate of patients with high expression of mPGES and/or PGI2 was lower than that of the low expression group. Cox regression analysis showed that the expression of mPGES and PGI2 had statistical significance in predicting the prognosis of lung cancer. CONCLUSIONS The cPLA2-AA-COX-2 pathway is closely associated with lung cancer. These findings are important for clinical diagnosis of lung cancer.

Integrated omics-based pathway analyses uncover CYP epoxygenase-associated networks as theranostic targets for metastatic triple negative breast cancer.

BACKGROUND: Current prognostic tools and targeted therapeutic approaches have limited value for metastatic triple negative breast cancer (TNBC). Building upon current knowledge, we hypothesized that epoxyeicosatrienoic acids (EETs) and related CYP450 epoxygenases may have differential roles in breast cancer signaling, and better understanding of which may uncover potential directions for molecular stratification and personalized therapy for TNBC patients. METHODS: We analyzed the oxylipin metabolome of paired tumors and adjacent normal mammary tissues from patients with pathologically confirmed breast cancer (N = 62). We used multivariate statistical analysis to identify important metabolite contributors and to determine the predictive power of tumor tissue metabolite clustering. In vitro functional assays using a panel of breast cancer cell lines were carried out to further confirm the crucial roles of endogenous and exogenous EETs in the metastasis transformation of TNBC cells. Deregulation of associated downstream signaling networks associated with EETs/CYPs was established using transcriptomics datasets from The Cancer Genome Atlas (TCGA) and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC). Comparative TNBC proteomics using the same tissue specimens subjected to oxylipin metabolomics analysis was used as validation set. RESULTS: Metabolite-by-metabolite comparison, tumor immunoreactivity, and gene expression analyses showed that CYP epoxygenases and arachidonic acid-epoxygenation products, EET metabolites, are strongly associated with TNBC metastasis. Notably, all the 4 EET isomers (5,6-, 8,9-, 11,12-, and 14,15-EET) was observed to profoundly drive the metastasis transformation of mesenchymal-like TNBC cells among the TNBC (basal- and mesenchymal-like), HER2-overexpressing and luminal breast cancer cell lines examined. Our pathway analysis revealed that, in hormone-positive breast cancer subtype, CYP epoxygenase overexpression is more related to immune cell-associated signaling, while EET-mediated Myc, Ras, MAPK, EGFR, HIF-1α, and NOD1/2 signaling are the molecular vulnerabilities of metastatic CYP epoxygenase-overexpressing TNBC tumors. CONCLUSIONS: This study suggests that categorizing breast tumors according to their EET metabolite ratio classifiers and CYP epoxygenase profiles may be useful for prognostic and therapeutic assessment. Modulation of CYP epoxygenase and EET-mediated signaling networks may offer an effective approach for personalized treatment of breast cancer, and may be an effective intervention option for metastatic TNBC patients.

HBx-K130M/V131I Promotes Liver Cancer in Transgenic Mice via AKT/FOXO1 Signaling Pathway and Arachidonic Acid Metabolism.

Chronic hepatitis B viral (HBV) infection remains a high underlying cause for hepatocellular carcinoma (HCC) worldwide, while the genetic mechanisms behind this remain unclear. This study elucidated the mechanisms contributing to tumor development induced by the HBV X (HBx) gene of predominantly Asian genotype B HBV and its common HBx variants. To compare the potential tumorigenic effects of K130M/V131I (Mut) and wild-type (WT) HBx on HCC, the Sleeping Beauty (SB) transposon system was used to deliver HBx Mut and WT into the livers of fumarylacetoacetate hydrolase (Fah)-deficient mice and in the context of transformation related protein 53 (Trp53) deficiency. From our results, HBx Mut had a stronger tumorigenic effect than its WT variant. Also, inflammation, necrosis, and fibrosis were evident in HBx experimental animals. Reduction of forkhead box O1 (FOXO1) with increased phosphorylation of upstream serine/threonine kinase (AKT) was detected under HBx Mut overexpression. Thus, it is proposed that HBx Mut enhances disease progression by reducing FOXO1 via phosphorylation of AKT. At the metabolomic level, HBx altered the expression of genes that participated in arachidonic acid (AA) metabolism, as a result of inflammation via accumulation of proinflammatory factors such as prostaglandins and leukotriene in liver. Taken together, the increased rate of HCC observed in chronic hepatitis B patients with K130M/V131I-mutated X protein, may be due to changes in AA metabolism and AKT/FOXO1 signaling. IMPLICATIONS: Our findings suggested that HBx-K130M/V131I-mutant variant promoted HCC progression by activating AKT/FOXO1 pathway and inducing stronger inflammation in liver via AA metabolism.

Pparγ Is Involved in the Transcriptional Regulation of Liver LC-PUFA Biosynthesis by Targeting the Δ6Δ5 Fatty Acyl Desaturase Gene in the Marine Teleost Siganus canaliculatus.

As the first marine teleost demonstrated to have the ability of long-chain polyunsaturated fatty acids (LC-PUFA) biosynthesis from C18 PUFA precursors, the rabbitfish Siganus canaliculatus provides us a unique model for clarifying the regulatory mechanisms of LC-PUFA biosynthesis in teleosts aiming at the replacement of dietary fish oil (rich in LC-PUFA) with vegetable oils (rich in C18 PUFA precursors but devoid of LC-PUFA). In the study of transcription regulation of gene encoding the Δ6Δ5 fatty acyl desaturase (Δ6Δ5 Fads), a rate-limiting enzyme catalyzing the first step of LC-PUFA biosynthesis in rabbitfish, a binding site for the transcription factor (TF), peroxisome proliferator-activated receptor γ (Pparγ), was predicted in Δ6Δ5 fads2 promoter by bioinformatics analysis, and thus the present study focused on the regulatory roles of Pparγ on Δ6Δ5 fads2. First, the activity of the Δ6Δ5 fads2 promoter was proved to be downregulated by pparγ overexpression and upregulated by treatment of Pparγ antagonist (GW9662), respectively, in HEK 293T cells with the dual luciferase reporter assay. Pparγ was further confirmed to interact with the promoter by electrophoretic mobility shift assay. Moreover, in S. canaliculatus hepatocyte line (SCHL) cells, GW9662 decreased the expression of pparγ together with increase of Δ6Δ5 fads2 mRNA. Besides, Δ6Δ5 fads2 expression was increased by pparγ RNAi knockdown and reduced by its mRNA overexpression. Furthermore, knockdown of pparγ induced a high conversion of 18:3n-3 to 18:4n-3 and 18:2n-6 to 18:3n-6, while pparγ mRNA overexpression led to a lower conversion of that, and finally a significant decrease of 20:4n-6(ARA), 20:5n-3(EPA), and 22:6n-3(DHA) production. The results indicate that Pparγ is involved in the transcriptional regulation of liver LC-PUFA biosynthesis by targeting Δ6Δ5 fads2 in rabbitfish, which is the first report of Pparγ involvement in the regulation of LC-PUFA biosynthesis in teleosts.

The Cytochrome P450 Slow Metabolizers CYP2C9*2 and CYP2C9*3 Directly Regulate Tumorigenesis via Reduced Epoxyeicosatrienoic Acid Production.

Increased expression of cytochrome P450 CYP2C9, together with elevated levels of its products epoxyeicosatrienoic acids (EET), is associated with aggressiveness in cancer. Cytochrome P450 variants CYP2C9*2 and CYP2C9*3 encode proteins with reduced enzymatic activity, and individuals carrying these variants metabolize drugs more slowly than individuals with wild-type CYP2C9*1, potentially affecting their response to drugs and altering their risk of disease. Although genetic differences in CYP2C9-dependent oxidation of arachidonic acid (AA) have been reported, the roles of CYP2C9*2 and CYP2C9*3 in EET biosynthesis and their relevance to disease are unknown. Here, we report that CYP2C9*2 and CYP2C9*3 metabolize AA less efficiently than CYP2C9*1 and that they play a role in the progression of non-small cell lung cancer (NSCLC) via impaired EET biosynthesis. When injected into mice, NSCLC cells expressing CYP2C9*2 and CYP2C9*3 produced lower levels of EETs and developed fewer, smaller, and less vascularized tumors than cells expressing CYP2C9*1. Moreover, endothelial cells expressing these two variants proliferated and migrated less than cells expressing CYP2C*1. Purified CYP2C9*2 and CYP2C9*3 exhibited attenuated catalytic efficiency in producing EETs, primarily due to impaired reduction of these two variants by NADPH-P450 reductase. Loss-of-function SNPs within CYP2C9*2 and CYP2C9*3 were associated with improved survival in female cases of NSCLC. Thus, decreased EET biosynthesis represents a novel mechanism whereby CYPC29*2 and CYP2C9*3 exert a direct protective role in NSCLC development.Significance: These findings report single nucleotide polymorphisms in the human CYP2C9 genes, CYP2C9*2 and CYP2C9*3, exert a direct protective role in tumorigenesis by impairing EET biosynthesis. Cancer Res; 78(17); 4865-77. ©2018 AACR.

Multiplex genomewide association analysis of breast milk fatty acid composition extends the phenotypic association and potential selection of FADS1 variants to arachidonic acid, a critical infant micronutrient.

BACKGROUND: Breast milk is the sole nutrition source during exclusive breastfeeding, and polyunsaturated fatty acids (FAs) are critical micronutrients in infant physical and cognitive development. There has been no prior genomewide association study of breast milk, hence our objective was to test for genetic association with breast milk FA composition. METHODS: We measured the fractional composition of 26 individual FAs in breast milk samples from three cohorts totalling 1142 Bangladeshi mothers whose infants were genotyped on the Illumina MEGA chip and replicated on a custom Affymetrix 30K SNP array (n=616). Maternal genotypes were imputed using IMPUTE. RESULTS: After running 33 separate FA fraction phenotypes, we found that SNPs known to be associated with serum FAs in the FADS1/2/3 region were also associated with breast milk FA composition (experiment-wise significance threshold 4.2×10-9). Hypothesis-neutral comparison of the 33 fractions showed that the most significant genetic association at the FADS1/2/3 locus was with fraction of arachidonic acid (AA) at SNP rs174556, with a very large per major allele effect size of 17% higher breast milk AA level. There was no evidence of independent association at FADS1/2/3 with any other FA or SNP after conditioning on AA and rs174556. We also found novel significant experiment-wise SNP associations with: polyunsaturated fatty acid (PUFA) 6/PUFA3 ratio (sorting nexin 29), eicosenoic (intergenic) and capric (component of oligomeric Golgi complex 3) acids; and six additional loci at genomewide significance (<5×10-8). CONCLUSIONS: AA is the primary FA in breast milk influenced by genetic variation at the FADS1/2/3 locus, extending the potential phenotypes under genetic selection to include breast milk composition, thereby possibly affecting infant growth or cognition. Breast milk FA composition is influenced by maternal genetics in addition to diet and body composition.

Comprehensive genetic study of fatty acids helps explain the role of noncoding inflammatory bowel disease associated SNPs and fatty acid metabolism in disease pathogenesis.

Fatty acids and their derivatives play an important role in inflammation. Diet and genetics influence fatty acid profiles. Abnormalities of fatty acid profiles have been observed in inflammatory bowel diseases (IBD), a group of complex diseases defined by chronic gastrointestinal inflammation. IBD associated fatty acid profile abnormalities were observed independently of nutritional status or disease activity, suggesting a common genetic background. However, no study so far has attempted to look for overlap between IBD loci and fatty acid associated loci or investigate the genetics of fatty acid profiles in IBD. To this end, we conducted a comprehensive genetic study of fatty acid profiles in IBD using iCHIP, a custom microarray platform designed for deep sequencing of immune-mediated disease associated loci. This study identifies 10 loci associated with fatty acid profiles in IBD. The most significant associations were a locus near CBS (p = 7.62 × 10-8) and a locus in LRRK2 (p = 1.4 × 10-7). Of note, this study replicates the FADS gene cluster locus, previously associated with both fatty acid profiles and IBD pathogenesis. Furthermore, we identify 18 carbon chain trans-fatty acids (p = 1.12 × 10-3), total trans-fatty acids (p = 4.49 × 10-3), palmitic acid (p = 5.85 × 10-3) and arachidonic acid (p = 8.58 × 10-3) as significantly associated with IBD pathogenesis.

Associations among FADS1 rs174547, eicosapentaenoic acid/arachidonic acid ratio, and arterial stiffness in overweight subjects.

We aimed to evaluate the longitudinal interaction effects between the minor allele of FADS1 rs174547 and overweight on n-3 and n-6 long-chain polyunsaturated fatty acid (PUFA) levels and pulse wave velocity (PWV). Plasma PUFA levels were measured via GC-MS, and arterial stiffness was determined as brachial-ankle PWV (ba-PWV) at baseline and after a mean follow-up of 3 years. The FADS1 rs174547 T > C genotype was analyzed. At 3-years of follow-up, after adjustment for age, sex, smoking and drinking, there were interaction effects between the FADS1 rs174547 T > C genotype and baseline BMI on the changes (from baseline) in plasma arachidonic acid (AA) levels, in the eicosapentaenoic acid (EPA)/AA ratio, and in ba-PWV (p for interaction = 0.036, 0.022, and 0.001, respectively). There were smaller increases in AA levels from baseline among normal-weight C allele carriers (n = 112) and overweight TT subjects (n = 47) than among normal-weight TT subjects (n = 91). Overweight C allele carriers (n = 37) showed greater reductions in the plasma EPA/AA ratio and greater increases in ba-PWV than the 3 other populations studied. The minor allele of the FADS1 rs174547 polymorphism is associated with age-related decreases in the EPA/AA ratio and increases in ba-PWV among overweight subjects.

Oxidative Stress in HIV Infection and Alcohol Use: Role of Redox Signals in Modulation of Lipid Rafts and ATP-Binding Cassette Transporters.

AIMS: Human immunodeficiency virus (HIV) infection induces oxidative stress and alcohol use accelerates disease progression, subsequently causing immune dysfunction. However, HIV and alcohol impact on lipid rafts-mediated immune dysfunction remains unknown. In this study, we investigate the modulation by which oxidative stress induces reactive oxygen species (ROS) affecting redox expression, lipid rafts caveiloin-1, ATP-binding cassette (ABC) transporters, and transcriptional sterol regulatory element-binding protein (SREBP) gene and protein modification and how these mechanisms are associated with arachidonic acid (AA) metabolites in HIV positive alcohol users, and how they escalate immune dysfunction. RESULTS: In both alcohol using HIV-positive human subjects and in vitro studies of alcohol with HIV-1 gp120 protein in peripheral blood mononuclear cells, increased ROS production significantly affected redox expression in glutathione synthetase (GSS), super oxide dismutase (SOD), and glutathione peroxidase (GPx), and subsequently impacted lipid rafts Cav-1, ABC transporters ABCA1, ABCG1, ABCB1, and ABCG4, and SREBP transcription. The increased level of rate-limiting enzyme 3-hydroxy-3-methylglutaryl HMG-CoA reductase (HMGCR), subsequently, inhibited 7-dehydrocholesterol reductase (DHCR-7). Moreover, the expression of cyclooxygenase-2 (COX-2) and lipoxygenase-5 (5-LOX) mRNA and protein modification tentatively increased the levels of prostaglandin E2 synthases (PGE2) in plasma when compared with either HIV or alcohol alone. INNOVATION: This article suggests for the first time that the redox inhibition affects lipid rafts, ABC-transporter, and SREBP transcription and modulates AA metabolites, serving as an important intermediate signaling network during immune cell dysfunction in HIV-positive alcohol users. CONCLUSION: These findings indicate that HIV infection induces oxidative stress and redox inhibition, affecting lipid rafts and ABC transports, subsequently upregulating AA metabolites and leading to immune toxicity, and further exacerbation with alcohol use. Antioxid. Redox Signal. 28, 324-337.