Arachidonic Research Articles

Effects of saline-alkaline stress on metabolomics profiles, biochemical parameters, and liver histopathology in large yellow croaker (Larimichthys crocea)

China has several saline-alkaline bodies. Studies on the adaptation of fish in saline-alkaline conditions are important for the efficient utilization of such areas. In this study, we employed a comprehensive approach combining histopathological analysis, biochemical markers, and metabolomic profiling to examine the impact of saline-alkaline stress on the liver of the large yellow croaker (Larimichthys crocea). It was found that the survival rate of L. crocea in the saline-alkaline treated group (EX) was significantly higher than that of the control group (CK). Saline-alkaline stress could not influence the structure of the liver of L. crocea, and not change the levels of superoxide dismutase (SOD), catalase (CAT), alkaline phosphatase (ALP), acid phosphatase (ACP). In addition, we identified 5953 metabolites, and 312 differentially expressed metabolites (DEMs) showed significant differential expression between the CK and EX groups. In the positive ion mode, 216 DEMs were identified, including 120 up-regulated and 96 down-regulated DEMs, and in the negative ion mode, 178 DEMs were identified, including 131 up-regulated and 47 down-regulated DEMs. Pathway enrichment analysis revealed significant involvement in 58 metabolic pathways, primarily linked to energy metabolism. These included the metabolism of amino acid, carbohydrate, and lipid pathways, including cysteine and methionine metabolism, biosynthesis of valine, leucine, isoleucine, and ascorbate; aldarate metabolism; galactose metabolism; glycerophospholipid metabolism; and the biosynthesis of unsaturated fatty acids. Metabolomics revealed that increased synthesis of compounds, such as succinic acid, arachidonic acid, and L-gulonic acid in the liver of L.crocea, is associated with adaptation to saline-alkaline aquaculture conditions. The findings of this study indicated that the fish mitigate reactive oxygen species induced by hyperosmotic environments and improve cellular membrane fluidity and intercellular signal transduction through the metabolism of unsaturated fatty acids and carbohydrates, facilitating adaptation to saline-alkaline conditions.

COX-2 in lung cancer: Mechanisms, development, and targeted therapies.

Lung cancer (LC) is the leading cause of cancer-related death worldwide, with non-small cell lung cancer (NSCLC) comprising 85% of all cases. COX-2, an enzyme induced significantly under stress conditions, catalyzes the conversion of free arachidonic acid into prostaglandins. It exhibits high expression in various tumors and is closely linked to LC progression. COX-2 functions as a pivotal driver in cancer pathogenesis by promoting prostaglandin E2synthesis and facilitating tumor cell occurrence and development. Furthermore, COX-2 holds potential as a predictive marker for early-stage NSCLC, guiding targeted therapy in patients with early COX-2 overexpression. Additionally, combining COX-2 inhibitors with diverse treatment modalities enhances tumor therapeutic efficacy, minimizes adverse effects on healthy tissues, and improves overall patient survival rates posttreatment. In conclusion, combined therapy targeting COX-2 presents a promising novel strategy for NSCLC treatment, offering avenues for improving prognosis and effective tumor treatment. This review provides novel insights and ideas for developing new treatment strategies to improve the prognosis of NSCLC.

Positive effects of Lithospermum erythrorhizon extract added to high soybean meal diet on growth, intestinal antioxidant capacity, intestinal microbiota, and metabolism of pearl gentian grouper

This study aims to investigate the effects of adding 2‰ Lithospermum erythrorhizon (LE) extract to the high soybean meal diet on the growth, intestinal antioxidant capacity, intestinal microbes, and metabolism of pearl gentian grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂). Three diets included FM, SBM, and SBMLE, in which FM was the whole fish meal diet, SBM was the soybean meal replacing 50% fish meal protein, and SBMLE was the SBM diet supplemented with 2‰ LE extract. After a 56-day feeding trial, the results showed the weight gain rate (WGR), specific growth rate (SGR), and feed efficiency rate (FER) of pearl gentian grouper in FM and SBMLE group was significantly higher than that of SBM (P < 0.05). Furthermore, high soybean meal dietary added LE extract inclusion significantly increased the SOD, CAT, and GSH-Px activity while significantly decreasing the MDA level (P < 0.05). Significant differences were in the gene expression of cytokines il1-β, il8, tnf-α, il10, and tgf-β between the SBMLE and SBM groups (P < 0.05). In addition, Microbiomics results revealed increased ASVs and alterations in gut microbiota composition, characterized by a decrease in Bacteroidota and an increase in Proteobacteria, Nautella, and lactococcus after adding LE extract. Furthermore, the substantial reduction in Firmicutes and Acidobacterota induced by high soybean meal feed was reversed by LE extract. Metabolic pathway enrichment analysis showed that LE extract mitigated soybean-induced enteritis (SBMIE) by affecting two critical metabolic pathways: arachidonic acid metabolism and histidine metabolism. In conclusion, adding LE extract to a high soybean meal diet can improve the growth performance and immunity of the pearl gentian grouper, and LE can play a mitigating role in SBMIE by regulating lipid metabolism, amino acid metabolism, and intestinal flora balance.

N,N-Disubstituted 4-Sulfamoylbenzoic Acid Derivatives as Inhibitors of Cytosolic Phospholipase A2α: Synthesis, Aqueous Solubility, and Activity in a Vesicle and a Whole Blood Assay.

Cytosolic phospholipase A2α (cPLA2α) is the key enzyme that initiates the arachidonic acid cascade through which pro-inflammatory lipid mediators can be formed. Therefore, cPLA2α is considered an interesting target for the development of anti-inflammatory drugs. Although several effective inhibitors of the enzyme have been developed, none of them has yet reached clinical application. Recently, we have prepared new 4-sulfamoylbenzoic acid derivatives based on a cPLA2α inhibitor found in a ligand-based virtual screening. The most effective of these compounds were now subjected to further variations in which the substitution pattern on the sulfamoyl nitrogen atom was changed.. The new compounds were tested in vitro in a vesicle assay for cPLA2α inhibition as well as for their water solubility, metabolic stability, and selectivity towards related enzymes. In addition, they were evaluated ex vivo in a whole blood assay in which metabolites of the arachidonic acid cascade formed after activation of cPLA2α were quantified using a combined online dilution/ online solid phase extraction HPLC-MS method. Inhibitors with submicromolar inhibitory in vitro potency were found with favourable water solubility and selectivity. However, their efficacy did not match that of the highly effective, known, structurally related cPLA2α inhibitor giripladib, which was also tested as a reference. One advantage of some of the new compounds compared to giripladib was their significantly improved water solubility. When analyzing the substances in the ex vivo whole blood assay, it was found that the obtained inhibition data correlated better with the in vivo results when the phorbol ester 12-Otetradecanoylphorbol- 13-acetate was used for activation of the enzyme in the blood cells instead of the calcium ionophore A23187. New compounds with good activity towards cPLA2α and reasonable physicochemical properties were identified. Overall, the results obtained could be helpful in the development of clinically applicable inhibitors of this enzyme.

Plasmalogens in Innate Immune Cells: From Arachidonate Signaling to Ferroptosis

Polyunsaturated fatty acids such as arachidonic acid are indispensable components of innate immune signaling. Plasmalogens are glycerophospholipids with a vinyl ether bond in the sn-1 position of the glycerol backbone instead of the more common sn-1 ester bond present in “classical” glycerophospholipids. This kind of phospholipid is particularly rich in polyunsaturated fatty acids, especially arachidonic acid. In addition to or independently of the role of plasmalogens as major providers of free arachidonic acid for eicosanoid synthesis, plasmalogens also perform a varied number of functions. Membrane plasmalogen levels may determine parameters of the plasma membrane, such as fluidity and the formation of microdomains that are necessary for efficient signal transduction leading to optimal phagocytosis by macrophages. Also, plasmalogens may be instrumental for the execution of ferroptosis. This is a nonapoptotic form of cell death that is associated with oxidative stress. This review discusses recent data suggesting that, beyond their involvement in the cellular metabolism of arachidonic acid, the cells maintain stable pools of plasmalogens rich in polyunsaturated fatty acids for executing specific responses.

Abstract A023: Arachidonic acid metabolism promoting cross resistance in melanoma cells

Abstract Melanoma patients initially respond well to first line immunotherapy. However, cross resistance to immunotherapy and BRAF/MEK inhibitor is a clinical challenge for melanoma care. To investigate drug tolerant and resistant mechanisms promoting cross resistance, we analyzed RNA-sequencing and gene set enrichment targeted therapy resistant melanoma cells revealing an enriched arachidonic acid gene signature. Intracellular arachidonic acid levels were increased in drug resistant and drug tolerant melanoma models. Arachidonic acid is enzymatically converted by COX1 and COX2 to prostaglandins, which is subsequently secreted into the microenvironment. Drug tolerant and resistant cells had increased protein expression of COX1 and COX2 concurrently with increased secretion of prostaglandin E2. COX1/2 inhibition and COX2 knockdown in vitro had no effect on cell growth in drug tolerant or resistant cells compared to parental cells. However, secreted prostaglandins are known immunomodulators, thus we explored how COX1/2 inhibition in combination with BRAF inhibitor plus MEK inhibitor affected immune cell infiltration. COX1/2 inhibition increased CD4+ and CD8+ T cell infiltration as compared to BRAF inhibitor plus MEK inhibitor alone. Under constant BRAF inhibitor plus MEK inhibitor treatment, we found that COX1/2 inhibition upon reaching MRD status prevented tumor relapse in vivo and increased survival dependent on an immune system. Future studies will evaluate the importance of arachidonic acid metabolism in promoting cross resistance to immune checkpoint blockade and whether T cell depletion prevents the delayed tumor relapse. Overall, COX1/2 inhibition delayed tumor relapse and survival in an immune-dependent manner and demonstrated a potential cross resistant mechanism. Citation Format: Casey D. Stefanski, Daniel A. Erkes, Timothy J. Purwin, Glenn L. Mersky, Erica L. Kitterman, Manal Mustafa, Jelan Haj, Diana Melissaratos, Andrew E. Aplin. Arachidonic acid metabolism promoting cross resistance in melanoma cells [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr A023.

The factor XI/XIa antibody abelacimab combined with enoxaparin inhibits filter clotting in hemodialysis circuits ex vivo.

Drugs targeting factor XI may offer an alternative to heparin for preventing blood clotting in extracorporeal circulation. We investigated the effects of abelacimab, a novel monoclonal antibody targeting factor XI. We collected whole blood samples into two bags (each 240ml, control group: enoxaparin 1.2mg, treatment group: enoxaparin 1.2mg plus abelacimab 5mg) and circulated in a hemodialysis device for up to 3h. We performed whole blood aggregation and thromboelastometry at several time points. Time to filter clotting was the primary endpoint. We included 10 volunteers. Each volunteer's blood was split into two bags (containing enoxaparin +/- abelacimab) and used simultaneously on two hemodialysis devices. The treatment group's time to filter clotting was significantly prolonged (treatment: 180min, IQR 180-180 vs. control: 120min, IQR 97-147, p < 0.001), and the transmembrane pressure was significantly lower at the end of the circuit flow (treatment: 13 mmHg vs. control: 65 mmHg, p = 0.001). Fibrinogen levels and median platelet counts were preserved. Platelet aggregation was better preserved in the treatment group for ristocetin (p = 0.015), thrombin receptor activating peptide (p = 0.015), and arachidonic acid (p = 0.001). Thromboelastometry showed prolonged clotting times in the treatment group at the end of the experiment (INTEM, p < 0.001; HEPTEM, p = 0.001). Abelacimab prolonged the time to filter clotting in this ex vivo model of hemodialysis. This is an aggressive model due to the frequent re-circulation of blood and a lack of endothelial cells. These data provide support for testing abelacimab in patients on hemodialysis.

Multidimensional Plasma Lipids Affect Preeclampsia/Eclampsia: A Mendelian Randomization Study.

Circulating lipids play a crucial role during pregnancy and may impact various pregnancy-related diseases. This study employed a two-sample Mendelian randomization (MR) framework to investigate the causal relationship between alterations in multidimensional plasma lipid levels and the risk of preeclampsia or eclampsia, offering deeper insight into this association. The inverse variance weighted (IVW) method was utilized as the main analysis. Summary statistics from plasma lipidomics of 7174 Finnish individuals and summary data on preeclampsia/eclampsia from the FinnGen consortium involving 219 817 European participants were employed. Sensitivity analyses were conducted to evaluate heterogeneity and pleiotropy. The study identified 17 lipid species from a total of 179 lipid species associated with susceptibility to preeclampsia/eclampsia. Notably, ten species, including six triacylglycerols (TAGs) (50:1, 48:1, 56:4, 49:2, 48:2, 54:3), a diacylglycerol (DAG) (16:1_18:1), and three sphingomyelins (SMs) (d36:1, d34:1, d38:1), were found to increase the risk of preeclampsia/eclampsia. Conversely, seven species, including five phosphatidylcholines (PCs) (16:1_20:4, O-18:1_20:4, 18:1_20:4, 16:0_20:4, 17:0_20:4) and two phosphatidylethanolamines (PEAs) (18:0_20:4, 16:0_20:4), all containing arachidonic acid (ARA) in the sn-2 position, were associated with a reduced risk of preeclampsia/eclampsia (all p < 0.05). The results of thestratified analysis were consistent with these findings. Furthermore, reverse MR analysis indicated that preeclampsia/eclampsia does not causally affect plasma levels of these lipids. Our findings established a causal relationship between specific plasma lipid species and modulation of preeclampsia/eclampsia risk, providing improved resolution for risk assessment and potential therapeutic targets in the disease.

Lipophilic index of serum phospholipids in patients with type 2 diabetes and atherosclerotic cardiovascular disease: links with metabolic control, vascular inflammation and platelet activation.

Little is known about the mechanisms underlying the association of the serum phospholipid lipophilic index (LI) with atherosclerotic cardiovascular disease (ASCVD) in patients with type 2 diabetes (T2D). Therefore, we investigated whether the LI is associated with glucometabolic control, meta-inflammation, thrombin generation, fibrin clot properties, endothelial function and platelet activation in T2D patients with angiographically documented ASCVD. We studied 74 T2D patients with ASCVD, aged 65.6 ± 6.8 years, with a median diabetes duration of 10 years and median HbA1c of 7.0%. Serum phospholipid fatty acids (FAs) were measured by gas chromatography. The serum phospholipid LI was calculated as the sum of the products of the proportion (% of total FAs) with the melting points (°C) of each individual FA, divided by the sum of the proportions of all FAs. Levels of HbA1c, insulin, leptin, adiponectin, lipid profiles, inflammatory markers (hsCRP, interleukin-6, TNF-α), Lp-PLA2 (a biomarker of vascular inflammation), endothelial function (sICAM-1, sVCAM-1, FMD, NMD), thrombin generation, fibrin clot properties and platelet activation, measured by light transmission aggregometry with arachidonic acid [AA] and adenosine diphosphate [ADP], were assessed. Patients with LI > 16.9°C (median) had higher HbA1c concentrations by 5.9% compared to the remaining subjects (p = 0.035). In this group, HbA1c levels ≥ 7.0% were found more often than in individuals with LI ≤ 16.9°C (62.2 vs. 35.1%; p = 0.020). Subjects with LI > 16.9°C had higher levels of TCh by 17.1% (p = 0.012), LDL-Ch by 29.4% (p = 0.003), interleukin-6 by 22.2% (p = 0.031) and Lp-PLA2 by 32.4% (p = 0.040), compared to the remaining patients. Moreover, they had increased maximal platelet aggregation induced by AA (p = 0.045), but not by ADP. Serum phospholipid LI correlated with HbA1c (r = 0.24; p = 0.037), TCh (r = 0.36; p = 0.002), LDL-Ch (r = 0.38; p < 0.001), interleukin-6 (r = 0.27; p = 0.020) and Lp-PLA2 (r = 0.26; p = 0.026). There were no intergroup differences in endothelial function, thrombin generation and fibrin clot properties. Regression analysis showed that HbA1c ≥ 7.0% and serum levels of LDL-Ch, interleukin-6 and Lp-PLA2 were predictors of LI > 16.9°C in adjusted models. In well-controlled T2D patients with ASCVD, the higher serum phospholipid LI is associated with worse glucometabolic control, enhanced vascular inflammation and higher platelet reactivity during aspirin treatment at cyclooxygenase-1-selective doses.

11C]PS13 Demonstrates Pharmacologically Selective and Substantial Binding to Cyclooxygenase-1 in the Human Brain.

Our laboratory recently developed [11C]PS13 as a PET radioligand to selectively measure cyclooxygenase-1 (COX-1). The cyclooxygenase enzyme family converts arachidonic acid into prostaglandins and thromboxanes, which mediate inflammation. The total brain uptake of [11C]PS13, which is composed of both specific binding and background uptake, can be accurately quantified with gold standard methods of compartmental modeling. This study sought to quantify the specific binding of [11C]PS13 to COX-1 in healthy human brain using scans performed with arterial input function at baseline and after blockade by the COX-1-selective inhibitor ketoprofen. Methods: Eight healthy volunteers underwent two 90-min [11C]PS13 PET scans with radiometabolite-corrected arterial input function, at baseline and about 2 h after oral administration of ketoprofen (75 mg). Results: Two-tissue compartment modeling effectively identified the total uptake of radioactivity in the brain (as distribution volume), showing the highest densities in the hippocampus, the occipital cortex, and the banks of the central sulcus. All brain regions exhibited displaceable and specific binding, and thus none could be used as a reference region. Ketoprofen blocked approximately 84% of the binding sites on COX-1 in the whole brain. After full occupancy was extrapolated, the average whole-brain values of [11C]PS13 were 1.6 ± 0.8 mL·cm-3 for specific uptake, 1.7 ± 0.6 mL·cm-3 for background uptake, and 1.1 ± 0.5 for the specific-to-background ratio. The hippocampus had the highest specific-to-background ratio value of 2.7 ± 0.9. Conclusion: [11C]PS13 exhibited high specific binding to COX-1 in the human brain, but its quantification requires arterial blood sampling.

Bacteriocin Microcin J25's antibacterial infection effects and novel non-microbial regulatory mechanisms: differential regulation of dopaminergic receptors.

The antibacterial and immunomodulatory activities of bacteriocins make them attractive targets for development as anti-infective drugs. Although the importance of the enteric nervous system (ENS) in the struggle against infections of the intestine has been demonstrated, whether it is involved in bacteriocins anti-infective mechanisms is poorly defined. Here, we demonstrated that the bacteriocin Microcin J25 (J25) significantly alleviated diarrhea and intestinal inflammation in piglets caused by enterotoxigenic Escherichia coli (ETEC) infection. Mechanistically, macrophage levels were significantly downregulated after J25 treatment, and this was replicated in a mouse model. Omics analysis and validation screening revealed that J25 treatment induced significant changes in the dopaminergic neuron pathway, but little change in microbial structure. The alleviation of inflammation may occur by down-regulating dopamine receptor (DR) D1 and the downstream DAG-PKC pathway, thus inhibiting arachidonic acid decomposition, and the inhibition of macrophages may occur through the up-regulation of DRD5 and the downstream cAMP-PKA pathway, thus inhibiting NF-κB. Our studies' findings provide insight into the changes and possible roles of the ENS in J25 treatment of ETEC infection, providing a more sophisticated foundational understanding for developing the application potential of J25.

Discovery and Molecular Characterization of a Novel 9S-Lipoxygenase from Enhygromyxa salina for Fatty Acid Biotransformations.

Iron-dependent lipoxygenases (LOXs) are involved in the synthesis of oxylipins from polyunsaturated fatty acids. However, they are usually difficult to overexpress in functional form in microbial cell factories. Moreover, 9-LOXs, generating 9-hydroperoxy fatty acids from C18 polyunsaturated fatty acids, have rarely been found from microbial sources. Here, we discovered a novel 9S-LOX in the marine myxobacterium Enhygromyxa salina (Es-9S-LOX). The recombinant enzyme produced in Escherichia coli exhibited remarkable activity in the dioxygenation of linoleic acid (LA, 1), α-linolenic acid, γ-linolenic acid, and arachidonic acid specifically at the C9 position to yield the product with (S)-configuration at catalytic efficiency of 3.94, 1.42, 1.38, and 0.69 μM-1·s-1, respectively. The elucidated X-ray crystal structure of Es-9S-LOX reveals a long and narrow hydrophobic pocket that allows the substrate to be near the metal ion and the oxygen tunnel. The enzyme was successfully used in a chemoenzymatic reaction to generate a hydroxy fatty acid from LA. Our study thus contributes to the valorization of renewable polyunsaturated fatty acids into a variety of fatty acid derivatives, including hydroxy fatty acids.

Melatonin alleviates heat stress-induced spermatogenesis dysfunction in male dairy goats by regulating arachidonic acid metabolism mediated by remodeling the gut microbiota.

Heat stress (HS) commonly occurring in summer has gradually become a factor threatening the reproductive performance of male dairy goats by reducing their fecundity. Despite the melatonin is applied to relieve HS, it is still unclear whether melatonin protects against reproductive damage induced by HS in dairy goats and how it works. The purpose of the present study is to evaluate the role of melatonin in alleviating HS-induced spermatogenesis dysfunction in male dairy goats and further explore its mechanism. HS impaired spermatogenesis, sperm formation in the testes, and sperm maturation in the epididymis of dairy goats, resulting in decreased sperm quality. Melatonin rescued the decrease of sperm quality induced by HS via decreasing inflammatory and oxidative stress levels in testicular tissue and enhancing intercellular barrier function within the testes. Amplicon-based microbiota analysis revealed that despite gut microbiota differences between melatonin-treated dairy goats and NC dairy goats to some extent, melatonin administration tends to return the gut microbiota of male dairy goats under HS to the levels of natural control dairy goats. To explore whether the protective role of melatonin in sperm quality is mediated by regulating gut microbiota, fecal microbiota of HS dairy goats with or without melatonin treatment were transferred to HS mice, respectively. We found HS mice that had received fecal bacteria of HS dairy goats experienced serious testicular injury and dyszoospermia, while this phenomenon was ameliorated in HS mice that had received fecal bacteria of dairy goats treated with melatonin, indicating melatonin alleviates HS-induced spermatogenic damage in a microbiota dependent manner. We further found that the testicular tissue of both HS dairy goats and mice transplanted with HS dairy goat feces produced large amounts of arachidonic acid (AA)-related metabolites, which were closely associated with semen quality. Consistently, supplementation with AA has been shown to elevate the levels of inflammation and oxidative stress in the testicular tissue of mice, disrupting intercellular connections and ultimately leading to spermatogenic disorders. This study has revealed that melatonin can effectively alleviate spermatogenic disorders in dairy goats caused by HS. This beneficial effect was primarily achieved through the modulation of gut microbiota, which subsequently inhibited the excessive synthesis of AA in testicular tissue. These discoveries are of great significance for preventing or improving the decline in male livestock reproductive performance caused by HS, enhancing the reproductive efficiency of elite male breeds, and ultimately improving the production efficiency of animal husbandry. Video Abstract.

Abstract 4134926: Association of Eicosanoid Metabolites with Body Mass Index

Introduction: The specific molecular pathways from obesity to inflammation to cardiovascular disease remain unclear. Eicosanoids are a unique class of bioactive lipids that govern the upstream initiation of pro- and anti-inflammatory activity. Objective: We leveraged a novel lipidomic platform to quantify &gt; 800 eicosanoid metabolites and examined their association with body mass index (BMI). Methods: We studied Multi-Ethnic Study of Atherosclerosis (MESA) participants with available samples for eicosanoid analysis. Eicosanoids and related metabolites were assessed using a directed, non-targeted mass spectrometry-based platform. We examined the cross-sectional association of eicosanoid metabolites with BMI using multivariable linear regression models. Analyses were considered significant at FDR q-value &lt;0.01. Results: A total of 5101 individuals (age 63 ± 10 years; 53% women, 60% non-Whites) were included. The mean BMI was 28.3 ± 5.1 kg/m2. Of 811 eicosanoids analyzed, 255 showed a significant association with BMI (see Figure for putative metabolite identities; FDR q-value &lt;0.01 for all). Derivatives of docosahexaenoic acid (DHA; 19,20 DiHDPA, β = - 0.206, standard error [SE] = 0.013) and eicosatetraenoic acid (11(S) HEPE, β = - 0.180, SE = 0.014) were associated with lower BMI. Linoleic acid derivatives (12,13 diHOME, an exercise-induced lipokine) had a similar association. Conversely, derivatives of linoleic acid (13-oxoODE, β = 0.241, SE = 0.01) and arachidonic acid (11-HETE, β = 0.236, SE = 0.017) were associated with higher BMI. Other derivatives of linoleic acid (15 (S) HETrE) and prostaglandin (11b PGF2α) were also associated with higher BMI. Conclusions: We found that specific eicosanoid metabolites, including DHA and linoleic acid derivatives with known anti-inflammatory, atheroprotective, and beneficial metabolic effects (e.g., 19,20 DiHDPA; 12,13 diHOME), were associated with lower BMI. By contrast, specific arachidonic acid and prostaglandin derivatives with known pro-inflammatory and adverse CV effects (e.g. oxylipin 11-HETE; PGF2α; 13-oxoODE) were associated with higher BMI. These findings further the understanding of specific inflammatory pathways underlying the development of obesity-related CVD.

The Altered Lipid Composition and Key Lipid Metabolic Enzymes in Thiacloprid-Resistant Myzus persicae, with Special Attention Paid to the Function of MpTHEM6a

Neonicotinoid resistance is increasingly prevalent in the agricultural pest Myzus persicae. Lipids play a critical role in insect defense systems, but their contribution to insect neonicotinoid resistance is disregarded. We conducted metabolomics and transcriptomics studies on M. persicae thiacloprid-resistant (THG-R) and -susceptible (FFJ-S) populations. A total of 149 lipid metabolites were identified, with 90 upregulated and 59 downregulated in THG-R compared to in FFJ-S. Metabolites in the arachidonic acid (AA) pathway substantially varied between THG-R and FFJ-S. For example, arachidonic acid, (±)11-HETE, and prostaglandin B1 were significantly upregulated, while prostaglandin A1, tetranor-PGDM, 8,15-diHETE, and (±)11(12)-EET were significantly decreased in THG-R. Transcriptomics profiles and qPCR indicated that lipid metabolic enzymes, including fatty acid synthase (FAS), the elongase of very-long-chain fatty acids (ELO), fatty acid desaturase (FAD), and phospholipase (PL) genes, were not overexpressed in THG-R. Among the twelve thioesterase genes, only MpTHEM6a was significantly upregulated in THG-R. Knocking down the expression of MpTHEM6a in THG-R significantly increased the toxicity of the three neonicotinoids, reduced the lifespan of adults, and decreased the number of nonviable nymphs produced by female adults. The metabolites AA, (±)11-HETE, and prostaglandin B1 are potential biomarkers in neonicotinoid-resistant M. persicae. MpTHEM6a may become a potential target for combating neonicotinoid-resistant M. persicae.

Effects of the rs174575 single nucleotide polymorphism in FADS2 on levels of long-chain PUFA: a meta-analysis.

The influence of the SNP rs174575 (C/G) within the fatty acid desaturase 2 gene on the levels of long-chain PUFA was determined through statistical meta-analysis. Six databases were searched to retrieve the relevant literature. Original data were analysed using Stata 17·0, encompassing summary statistics, tests for heterogeneity, assessment of publication bias, subgroup analysis and sensitivity analysis. A total of ten studies were identified and grouped into twelve trials. Our results showed that individuals who carried the minor G allele of rs174575 had significantly higher dihomo-γ-linolenic acid levels (P = 0·005) and lower arachidonic acid levels (P = 0·033) than individuals who were homozygous for the major allele. The subgroup analysis revealed that the G-allele carriers of rs174575 were significantly positively correlated with linoleic acid (P = 0·002) and dihomo-γ-linolenic acid (P < 0·001) and negatively correlated with arachidonic acid (P = 0·004) in the European populations group. This particular SNP showed a potential association with higher concentrations of dihomo-γ-linolenic acid (P = 0·050) and lower concentrations of arachidonic acid (P = 0·030) within the breast milk group. This meta-analysis has been registered in the PROSPERO database (ID: CRD42023470562).

Associations of the serum n-6 PUFA concentrations with exercise-induced myocardial ischaemia in middle-aged and older men.

n-6 PUFA, especially linoleic acid (LA) but also arachidonic acid (AA), have been inversely associated with CHD. However, mechanisms underlying these associations are not fully known. We investigated the associations of the serum concentrations of total n-6 PUFA, LA, AA, γ-linolenic acid (GLA) and dihomo-γ-linolenic acid (DGLA), with the odds of myocardial ischaemia during exercise, a predictor of future cardiac events. A total of 1871 men without a history of CHD from the Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD) aged 42-60 years were included. All participants performed a maximal symptom-limited exercise stress test, using an electrically braked bicycle ergometer. Multivariable-adjusted logistic regression was used to assess the OR for exercise-induced myocardial ischaemia in quartiles of the serum n-6 PUFA concentrations. After multivariable adjustment, men in the highest v. the lowest serum AA concentration had 50 % lower odds for exercise-induced myocardial ischaemia (OR 0·50, 95 % CI 0·34, 0·76; P-trend across quartiles < 0·001). For the other PUFA, the OR (95 % CI) were 1·00 (0·69, 1·46; P-trend = 0·89) for LA, 1·07 (0·75, 1·53; P-trend = 0·40) for GLA and 0·74 (0·51, 1·07; P-trend = 0·16) for DGLA. Among the n-6 PUFA, higher serum concentration of AA was associated with lower odds for myocardial ischaemia during an exercise test in middle-aged and older men. This may provide one mechanism for the previously observed possible cardioprotective properties of AA. Our findings also suggest that n-6 PUFA should not be considered as one homogenous group.

Structural and Functional Biology of Mammalian ALOX Isoforms with Particular Emphasis on Enzyme Dimerization and Their Allosteric Properties

The human genome involves six functional arachidonic acid (AA) lipoxygenase (ALOX) genes, and the corresponding enzymes (ALOX15, ALOX15B, ALOX12, ALOX12B, ALOXE3, ALOX5) have been implicated in cell differentiations and in the pathogenesis of inflammatory, hyperproliferative, metabolic, and neurological disorders. Humans express two different AA 15-lipoxygenating ALOX isoforms, and these enzymes are called ALOX15 (15-LOX1) and ALOX15B (15-LOX2). Chromosomal localization, sequence alignments, and comparison of the enzyme properties suggest that pig and mouse ALOX15 orthologs (leukocyte-type 12-LOX) on the one hand and rabbit and human ALOX15 orthologs on the other (reticulocyte-type 15-LOX1) belong to the same enzyme family despite their different reaction specificities with AA as a substrate. In contrast, human ALOX12 (platelet-type 12-LOX), as well as pig and mouse ALOX15 (leukocyte-type 12-LOX), belong to different enzyme families, although they exhibit a similar reaction specificity with AA as a substrate. The complex multiplicity of mammalian ALOX isoforms and the controversial enzyme nomenclatures are highly confusing and prompted us to summarize the current knowledge on the biological functions, enzymatic properties, and allosteric regulation mechanisms of mammalian ALOX15, ALOX15B, and ALOX12 orthologs that belong to three different enzyme sub-families.

The potential clinical value of platelet aggregation in colorectal tumor progression

ObjectiveThe present study is to examine whether platelet aggregation function, platelet count and mean platelet volume are indicators that related to clinicopathological characteristics of colorectal cancer.MethodsA total of 546 patients with colorectal tumors and 118 healthy controls were enrolled, and patients with colorectal tumors were grouped according to malignancy, prognosis, recurrence and metastasis. The parameters of platelet aggregation function included max aggregation ratio, average aggregation ratio and max aggregation time were detected. 546 patients were induced by arachidonic acid, meanwhile, 415 of which were additionally induced by adenosine diphosphate. Of 118 healthy controls, 60 cases were induced by arachidonic acid and 58 cases were induced by adenosine diphosphate. We evaluated the intergroup significance of these indexes by receiver operating characteristic analysis.ResultsThe levels of max aggregation ratio, average aggregation ratio and platelet count were related to progression including cancerization, radical operation and recurrence and metastasis (P < 0.05). Notably, max aggregation ratio-arachidonic acid is the best indicator for predicting these three progressions with the areas under receiver operating characteristic curve of 0.685, 0.652, and 0.649, respectively.ConclusionCorrelations between max aggregation ratio, average aggregation ratio and colorectal tumor progression were observed with a certain clinical value.

Lipopolysaccharide-mediated effects of the microbiota on sleep and body temperature

Recent research suggests that microbial molecules translocated from the intestinal lumen into the host’s internal environment may play a role in various physiological functions, including sleep. Previously, we identified that butyrate, a short-chain fatty acid produced by intestinal bacteria, and lipoteichoic acid, a cell wall component of gram-positive bacteria, induce sleep when their naturally occurring translocation is mimicked by direct delivery into the portal vein. Building upon these findings, we aimed to explore the sleep signaling potential of intraportally administered lipopolysaccharide (LPS), a primary component of gram-negative bacterial cell walls, in rats. Low dose of LPS (1 μg/kg) increased sleep duration and prolonged fever, without affecting systemic LPS levels. Interestingly, administering LPS systemically outside the portal region at a dose 20 times higher did not affect sleep, indicating a localized sensitivity within the hepatoportal region for the sleep and febrile effects of LPS. Furthermore, both the sleep- and fever-inducing effects of LPS were inhibited by indomethacin, a prostaglandin synthesis inhibitor, and replicated by intraportal administration of prostaglandin E2 or arachidonic acid, suggesting the involvement of the prostaglandin system in mediating these actions.