Phenotyping drug polypharmacology via eicosanoid profiling of blood

Dual SPE-HPLC-MS/MS Platform for Cross-Class Antiparasitic Surveillance: Simultaneous Quantification of Oxyclozanide and Levamisole Hydrochloride in Ovine Tissues with Applications to Withdrawal Period Optimization

This study presents a novel high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for simultaneous determination of oxyclozanide (OXY) and levamisole hydrochloride (LEV) residues in ovine tissues, addressing the critical gap in cross-class antiparasitic drug monitoring. Leveraging dual solid-phase extraction strategies-MAX anion-exchange for lipophilic OXY and MCX cation-exchange for hydrophilic LEV-we achieved efficient purification of these pharmacokinetically divergent compounds from complex matrices (muscle, liver, kidney, and perirenal adipose). The method demonstrated superior sensitivity with limits of detection (1.5 μg/kg) and quantification (2.5 μg/kg) below international maximum residue limits (MRLs), validated through Codex Alimentarius guidelines (CAC/GL 71-2009). Linear responses (2.5-1000 μg/kg, R2 > 0.9900) and robust precision (intra-day RSD: 1.44-12.51%; inter-day RSD: 0.29-17.70%) were maintained across spiked concentrations (LOQ, 0.5×, 1×, and 2 × MRLs), with recoveries of 80.94-115.36% confirming matrix-agnostic accuracy. Stability assessments under diverse storage conditions further validated method reliability. Applied to pharmacokinetic profiling in medicated sheep, this protocol established a 28-day withdrawal period for edible tissues, reconciling regulatory compliance with food safety requirements. As the first reported simultaneous quantification platform for OXY and LEV antiparasitics, our methodology advances veterinary residue analytics by enabling efficient multi-class surveillance and evidence-based withdrawal period optimization.

Oxylipin profiling for clinical research: Current status and future perspectives

Oxylipins are potent lipid mediators with increasing interest in clinical research. They are usually measured in systemic circulation and can provide a wealth of information regarding key biological processes such as inflammation, vascular tone, or blood coagulation. Although procedures still require harmonization to generate comparable oxylipin datasets, performing comprehensive profiling of circulating oxylipins in large studies is feasible and no longer restricted by technical barriers. However, it is essential to improve and facilitate the biological interpretation of complex oxylipin profiles to truly leverage their potential in clinical research. This requires regular updating of our knowledge about the metabolism and the mode of action of oxylipins, and consideration of all factors that may influence circulating oxylipin profiles independently of the studied disease or condition. This review aims to provide the readers with updated and necessary information regarding oxylipin metabolism, their different forms in systemic circulation, the current limitations in deducing oxylipin cellular effects from in vitro bioactivity studies, the biological and technical confounding factors needed to consider for a proper interpretation of oxylipin profiles.

Toll-like receptor signaling induces a temporal switch towards a resolving lipid profile in monocyte-derived macrophages

Inflammation is a tightly regulated process. During the past decade it has become clear that the resolution of inflammation is an active process and its dysregulation can contribute to chronic inflammation. Several cells and soluble mediators, including lipid mediators, regulate the course of inflammation and its resolution. It is, however, unclear which signals and cells are involved in initiating the resolution process. Macrophages are tissue resident cells and key players in regulating tissue inflammation through secretion of soluble mediators, including lipids. We hypothesize that persistent inflammatory stimuli can initiate resolution pathways in macrophages. In this study, we detected 21 lipids in LPS-stimulated human monocyte-derived macrophages by liquid chromatography coupled to tandem mass spectrometry. Cyclooxygenase-derived Prostaglandins were observed in the first six hours of stimulation. Interestingly, a switch towards 15-lipoxygenase products, such as the pro-resolving lipid precursors 15-HEPE and 17-HDHA was observed after 24 h. The RNA and protein expression of cyclooxygenase and 15-lipoxygenase were in line with this trend. Treatment with 17-HDHA increased IL-10 production of monocyte-derived macrophages and decreased LTB₄ production by neutrophils, indicating the anti-inflammatory property of this lipid. These data reveal that monocyte-derived macrophages contribute to the resolution of inflammation in time by the production of pro-resolving lipids after an initial inflammatory stimulus.

The compatibility effects of sini decoction against doxorubicin-induced heart failure in rats revealed by mass spectrometry-based serum metabolite profiling and computational analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Sini decoction (SND) is a famous Traditional Chinese Medicine (TCM) formula composed of Acontium carmichaeli, Zingiber officinale and Glycyrrhiza uralensis, which is considered as an efficient formula against doxorubicin (DOX)-induced heart failure. But the compatibility mechanism of SND remains unclear.

AIM OF THE STUDY

The present study aimed to investigate the compatibility mechanism of SND against DOX-induced heart failure in rats.

MATERIALS AND METHODS

Mass spectrometry-based serum metabolomics were performed. The relative distance values (RDVs) of SND, A. carmichaeli-free decoction (ACFD), Z. officinale-free decoction (ZOFD) and G. uralensis-free decoction (GUFD) treated groups from the control/DOX groups in multidimensional space were calculated to provide a measure of compatibility effect of SND. SND, ACFD, ZOFD, GUFD-targeted metabolic pathways were identified and compared to investigate the synergistic mechanism of SND by computational systems analysis. Real-time quantitative PCR was further employed to validate the key metabolic pathways at the level of the gene.

RESULTS

The RDVs combined with the hemodynamic and biochemical analysis showed that the protection effects were sorted as SND > GUFD > ZOFD > ACFD. It revealed that DOX-induced heart failure perturbed 16 metabolic pathways, and SND, GUFD, ZOFD and ACFD-treated groups could significantly reversed 12, 10, 7 and 6 metabolic pathways of these 16 metabolic pathways, respectively. Metabolic pathway and RT-PCR analysis indicated that both SND and GUFD could protect DOX-induced heart failure mainly by regulating PLA2-COX pathway and PLA2-CYP pathway.

CONCLUSION

It can be concluded that A. carmichaeli played an essential role in attenuation of DOX-induced heart failure among the three herb constituents of SND and the constituent herbs mutually reinforced each other. This work demonstrated that metabolomics combined with computational systems analysis was a promising tool for uncovering the compatibility effects of TCM.

Clinical blood sampling for oxylipin analysis - effect of storage and pneumatic tube transport of blood on free and total oxylipin profile in human plasma and serum

Quantitative analysis of oxylipins in blood samples is of increasing interest in clinical studies. However, storage after sampling and transport of blood might induce artificial changes in the apparent oxylipin profile due to ex vivo formation/degradation by autoxidation or enzymatic activity. In the present study we investigated the stability of free (i.e. non-esterified) and total oxylipins in EDTA-plasma and serum generated under clinical conditions assessing delays in sample processing and automated transportation: Free cytochrome P450 monooxygenase and 5-lipoxygenase (LOX) formed oxylipins as well as autoxidation products were marginally affected by storage of whole blood up to 4 h at 4 °C, while total (i.e. the sum of free and esterified) levels of these oxylipins were stable up to 24 h and following transport. Cyclooxygenase (COX) products (TxB₂, 12-HHT) and 12-LOX derived hydroxy-fatty acids were prone to storage and transport induced changes due to platelet activation. Total oxylipin patterns were generally more stable than the concentration of free oxylipins. In serum, coagulation induced higher levels of COX and 12-LOX products showing a high inter-individual variability. Overall, our results indicate that total EDTA-plasma oxylipins are the most stable blood oxylipin marker for clinical samples. Here, storage of blood before further processing is acceptable for a period up to 24 hours at 4 °C. However, levels of platelet derived oxylipins should be interpreted with caution regarding potential ex vivo formation.

Promiscuous Ligands from Experimentally Determined Structures, Binding Conformations, and Protein Family-Dependent Interaction Hotspots

Compound promiscuity is often attributed to nonspecific binding or assay artifacts. On the other hand, it is well-known that many pharmaceutically relevant compounds are capable of engaging multiple targets in vivo, giving rise to polypharmacology. To explore and better understand promiscuous binding characteristics of small molecules, we have searched X-ray structures (and very few qualifying solution structures) for ligands that bind to multiple distantly related or unrelated target proteins. Experimental structures of a given ligand bound to different targets represent high-confidence data for exploring promiscuous binding events. A total of 192 ligands were identified that formed crystallographic complexes with proteins from different families and for which activity data were available. These "multifamily" compounds included endogenous ligands and were often more polar than other bound compounds and active in the submicromolar range. Unexpectedly, many promiscuous ligands displayed conserved or similar binding conformations in different active sites. Others were found to conformationally adjust to binding sites of different architectures. A comprehensive analysis of ligand-target interactions revealed that multifamily ligands frequently formed different interaction hotspots in binding sites, even if their bound conformations were similar, thus providing a rationale for promiscuous binding events at the molecular level of detail. As a part of this work, all multifamily ligands we have identified and associated activity data are made freely available.

Targeted lipidomics reveals activation of resolution pathways in knee osteoarthritis in humans

OBJECTIVE

To investigate the presence of inflammation and resolution pathways in osteoarthritis (OA).

DESIGN

Tissues were obtained from knee OA patients and control rheumatoid arthritis (RA) patients. Cells in synovial fluid (SF) were visualized by flow cytometry. Cytokines and chemokines were measured by multiplex assay. Lipid mediators (LMs) were determined by targeted lipidomics using liquid-chromatography mass spectrometry.

RESULTS

SF of OA patients contained less cells, especially neutrophils, less cytokines and comparable levels of chemokines compared to RA controls. Thirty-seven lipids were detected in the soluble fraction of SF, including polyunsaturated fatty acids (PUFAs) and their pro-inflammatory and pro-resolving lipoxygenase (LOX) and cyclooxygenase (COX) pathway markers in both OA and RA patients. Among these, pro-inflammatory LM such as prostaglandin E₂ (PGE₂) and thromboxane B₂, as well as precursors and pathway markers of resolution such as 17-HDHA and 18-HEPE were detected. Interestingly, the pro-resolving lipid RvD2 could also be detected, but only in the insoluble fraction (cells and undigested matrix). Ratios of metabolites to their precursors indicated a lower activity of 5-LOX and 15-LOX in OA compared to RA, with no apparent differences in COX-derived products. Interestingly, synovial tissue and SF cells could produce 5-LOX and 15-LOX metabolites, indicating these cells as possible source of LM.

CONCLUSIONS

By using a state-of-the-art technique, we show for the first time that resolution pathways are present in OA patients. A better understanding of these pathways could guide us to more effective therapeutic approaches to inhibit inflammation and further structural damage in OA and RA.

A Single Amino Acid Difference between Mouse and Human 5-Lipoxygenase Activating Protein (FLAP) Explains the Speciation and Differential Pharmacology of Novel FLAP Inhibitors

5-Lipoxygenase activating protein (FLAP) plays a critical role in the metabolism of arachidonic acid to leukotriene A4, the precursor to the potent pro-inflammatory mediators leukotriene B4 and leukotriene C4 Studies with small molecule inhibitors of FLAP have led to the discovery of a drug binding pocket on the protein surface, and several pharmaceutical companies have developed compounds and performed clinical trials. Crystallographic studies and mutational analyses have contributed to a general understanding of compound binding modes. During our own efforts, we identified two unique chemical series. One series demonstrated strong inhibition of human FLAP but differential pharmacology across species and was completely inactive in assays with mouse or rat FLAP. The other series was active across rodent FLAP, as well as human and dog FLAP. Comparison of rodent and human FLAP amino acid sequences together with an analysis of a published crystal structure led to the identification of amino acid residue 24 in the floor of the putative binding pocket as a likely candidate for the observed speciation. On that basis, we tested compounds for binding to human G24A and mouse A24G FLAP mutant variants and compared the data to that generated for wild type human and mouse FLAP. These studies confirmed that a single amino acid mutation was sufficient to reverse the speciation observed in wild type FLAP. In addition, a PK/PD method was established in canines to enable preclinical profiling of mouse-inactive compounds.

Phytomedicine polypharmacology: Cancer therapy through modulating the tumor microenvironment and oxylipin dynamics

Integrative approaches in cancer therapy have recently been extended beyond the induction of cytotoxicity to controlling the tumor microenvironment and modulating inflammatory cascades and pathways such as lipid mediator biosynthesis and their dynamics. Profiling of important lipid messengers, such as oxylipins, produced as part of the physiological response to pharmacological stimuli, provides a unique opportunity to explore drug pharmacology and the possibilities for molecular management of cancer physiopathology. Whereas single targeted chemotherapeutic drugs commonly lack efficacy and invoke drug resistance and/or adverse effects in cancer patients, traditional herbal medicines are seen as bright prospects for treating complex diseases, such as cancers, in a systematic and holistic manner. Understanding the molecular mechanisms of traditional medicine and its bioactive chemical constituents may aid the modernization of herbal remedies and the discovery of novel phytoagents for cancer management. In this review, systems-based polypharmacology and studies to develop multi-target drugs or leads from phytomedicines and their derived natural products that may overcome the problems of current anti-cancer drugs, are proposed and summarized.

Pharmacological inhibition of eicosanoids and platelet-activating factor signaling impairs zymosan-induced release of IL-23 by dendritic cells

The engagement of the receptors for fungal patterns induces the expression of cytokines, the release of arachidonic acid, and the production of PGE2 in human dendritic cells (DC), but few data are available about other lipid mediators that may modulate DC function. The combined antagonism of leukotriene (LT) B4, cysteinyl-LT, and platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) inhibited IL23A mRNA expression in response to the fungal surrogate zymosan and to a lower extent TNFA (tumor necrosis factor-α) and CSF2 (granulocyte macrophage colony-stimulating factor) mRNA. The combination of lipid mediators and the lipid extract of zymosan-conditioned medium increased the induction of IL23A by LPS (bacterial lipopolysaccharide), thus suggesting that unlike LPS, zymosan elicits the production of mediators at a concentration enough for optimal response. Zymosan induced the release of LTB4, LTE4, 12-hydroxyeicosatetraenoic acid (12-HETE), and PAF C16:0. DC showed a high expression and detectable Ser663 phosphorylation of 5-lipoxygenase in response to zymosan, and a high expression and activity of LPCAT1/2 (lysophosphatidylcholine acyltransferase 1 and 2), the enzymes that incorporate acetate from acetyl-CoA into choline-containing lysophospholipids to produce PAF. Pharmacological modulation of the arachidonic acid cascade and the PAF receptor inhibited the binding of P-71Thr-ATF2 (activating transcription factor 2) to the IL23A promoter, thus mirroring their effects on the expression of IL23A mRNA and IL-23 protein. These results indicate that LTB4, cysteinyl-LT, and PAF, acting through their cognate G protein-coupled receptors, contribute to the phosphorylation of ATF2 and play a central role in IL23A promoter trans-activation and the cytokine signature induced by fungal patterns.

Polypharmacology of Small-Molecule Modulators of the 5-Lipoxygenase Activating Protein (FLAP) Observed via a High-throughput Lipidomics Platform

Leukotrienes (LTs) and related species are proinflammatory lipid mediators derived from arachidonic acid (AA) that have pathological roles in autoimmune and inflammatory conditions, cardiovascular diseases, and cancer. 5-Lipoxygenase activating protein (FLAP) plays a critical accessory role in the conversion of AA to LTA4, and its subsequent conversion to LTC4 by LTC4 synthase. Pharmacological inhibition of FLAP results in a loss of LT production by preventing the biosynthesis of both LTB4 and LTC4, making it an attractive target for the treatment of inflammatory diseases in which LTs likely play a role. Small-molecule (SM) drugs often exhibit polypharmacology through various pathways, which may explain the differential therapeutic efficacies of compounds sharing structural similarity. We have profiled a series of SM FLAP modulators for their selectivity across enzymes of AA cascade in human whole blood (HWB), using a recently developed LC/MS (liquid chromatography–mass spectrometry)-based high-throughput lipidomics platform that monitors 122 eicosanoids in multiplex. Highly efficient data acquisition coupled with fast and accurate data analysis allowed facile compound profiling from ex vivo study samples. This platform allowed us to quantitatively map the effects of those SMs on the entire AA cascade, demonstrating its potential to discriminate structurally related compounds.