CD300ld on neutrophils is required for tumour-driven immune suppression.

The immune-suppressive tumour microenvironment represents a major obstacle to effective immunotherapy1,2. Pathologically activated neutrophils, also known as polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs), are a critical component of the tumour microenvironment and have crucial roles in tumour progression and therapy resistance2-4. Identification of the key molecules on PMN-MDSCs is required to selectively target these cells for tumour treatment. Here, we performed an in vivo CRISPR-Cas9 screen in a tumour mouse model and identified CD300ld as a top candidate of tumour-favouring receptors. CD300ld is specifically expressed in normal neutrophils and is upregulated in PMN-MDSCs upon tumour-bearing. CD300ld knockout inhibits the development of multiple tumour types in a PMN-MDSC-dependent manner. CD300ld is required for the recruitment of PMN-MDSCs into tumours and their function to suppress T cell activation. CD300ld acts via the STAT3-S100A8/A9 axis, and knockout of Cd300ld reverses the tumour immune-suppressive microenvironment. CD300ld is upregulated in human cancers and shows an unfavourable correlation with patient survival. Blocking CD300ld activity inhibits tumour development and has synergistic effects with anti-PD1. Our study identifies CD300ld as a critical immune suppressor present on PMN-MDSCs, being required for tumour immune resistance and providing a potential target for cancer immunotherapy.

Caffeic acid alleviates cerebral ischemic injury in rats by resisting ferroptosis via Nrf2 signaling pathway.

There are few effective and safe neuroprotective agents for the treatment of ischemic stroke currently. Caffeic acid is a phenolic acid that widely exists in a number of plant species. Previous studies show that caffeic acid ameliorates brain injury in rats after cerebral ischemia/reperfusion. In this study we explored the protective mechanisms of caffeic acid against oxidative stress and ferroptosis in permanent cerebral ischemia. Ischemia stroke was induced on rats by permanent middle cerebral artery occlusion (pMCAO). Caffeic acid (0.4, 2, 10 mg·kg-1·d-1, i.g.) was administered to the rats for 3 consecutive days before or after the surgery. We showed that either pre-pMCAO or post-pMCAO administration of caffeic acid (2 mg·kg-1·d-1) effectively reduced the infarct volume and improved neurological outcome. The therapeutic time window could last to 2 h after pMCAO. We found that caffeic acid administration significantly reduced oxidative damage as well as neuroinflammation, and enhanced antioxidant capacity in pMCAO rat brain. We further demonstrated that caffeic acid down-regulated TFR1 and ACSL4, and up-regulated glutathione production through Nrf2 signaling pathway to resist ferroptosis in pMCAO rat brain and in oxygen glucose deprivation/reoxygenation (OGD/R)-treated SK-N-SH cells in vitro. Application of ML385, an Nrf2 inhibitor, blocked the neuroprotective effects of caffeic acid in both in vivo and in vitro models, evidenced by excessive accumulation of iron ions and inactivation of the ferroptosis defense system. In conclusion, caffeic acid inhibits oxidative stress-mediated neuronal death in pMCAO rat brain by regulating ferroptosis via Nrf2 signaling pathway. Caffeic acid might serve as a potential treatment to relieve brain injury after cerebral ischemia. Caffeic acid significantly attenuated cerebral ischemic injury and resisted ferroptosis both in vivo and in vitro. The regulation of Nrf2 by caffeic acid initiated the transcription of downstream target genes, which were shown to be anti-inflammatory, antioxidative and antiferroptotic. The effects of caffeic acid on neuroinflammation and ferroptosis in cerebral ischemia were explored in a primary microglia-neuron coculture system. Caffeic acid played a role in reducing neuroinflammation and resisting ferroptosis through the Nrf2 signaling pathway, which further suggested that caffeic acid might be a potential therapeutic method for alleviating brain injury after cerebral ischemia.

Effect and mechanism of gomisin D on the isoproterenol induced myocardial injury in H9C2 cells and mice.

We established myocardial injury models in vivo and in vitro to investigate the cardioprotective effect of gomisin D obtained from Schisandra chinensis. Gomisin D significantly inhibited isoproterenol-induced apoptosis and hypertrophy in H9C2 cells. Gomisin D decreased serum BNP, ANP, CK-MB, cTn-T levels and histopathological alterations, and inhibited myocardial hypertrophy in mice. In mechanisms research, gomisin D reversed ISO-induced accumulation of intracellular ROS and Ca2+. Gomisin D further improved mitochondrial energy metabolism disorders by regulating the TCA cycle. These results demonstrated that gomisin D had a significant effect on isoproterenol-induced myocardial injury by inhibiting oxidative stress, calcium overload and improving mitochondrial energy metabolism.

The genome of Corydalis reveals the evolution of benzylisoquinoline alkaloid biosynthesis in Ranunculales.

Species belonging to the order Ranunculales have attracted much attention because of their phylogenetic position as a sister group to all other eudicot lineages and their ability to produce unique yet diverse benzylisoquinoline alkaloids (BIAs). The Papaveraceae family in Ranunculales is often used as a model system for studying BIA biosynthesis. Here, we report the chromosome-level genome assembly of Corydalis tomentella, a species of Fumarioideae, one of the two subfamilies of Papaveraceae. Based on comparisons of sequenced Ranunculalean species, we present clear evidence of a shared whole-genome duplication (WGD) event that has occurred before the divergence of Ranunculales but after its divergence from other eudicot lineages. The C. tomentella genome enabled us to integrate isotopic labeling and comparative genomics to reconstruct the BIA biosynthetic pathway for both sanguinarine biosynthesis shared by papaveraceous species and the cavidine biosynthesis that is specific to Corydalis. Also, our comparative analysis revealed that gene duplications, especially tandem gene duplications, underlie the diversification of BIA biosynthetic pathways in Ranunculales. In particular, tandemly duplicated berberine bridge enzyme-like genes appear to be involved in cavidine biosynthesis. In conclusion, our study of the C. tomentella genome provides important insights into the occurrence of WGDs during the early evolution of eudicots, as well as into the evolution of BIA biosynthesis in Ranunculales.

Novel Strategy to Rapidly Profile and Identify Oxidized Species of Polysorbate 80 Using Ultra-High-Performance Liquid Chromatography Coupled with High-Resolution Mass Spectrometry.

Polysorbate 80 (PS80) is widely used as an excipient in vaccines and biopharmaceuticals. The oxidized species of PS80 have raised concern because of their potential to compromise product stability and pose a clinical risk. Analytical methods to profile and identify the oxidized species are hard to develop owing to their complexity and low abundance. Herein, a novel strategy was demonstrated to comprehensively profile and identify the oxidized species of PS80 using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. The characteristic fragmentation patterns of the oxidized species were obtained under the "all ions" scan mode. Then, 10 types of distinct fragments from oxidized oleates were identified and confirmed using two purified oxidized species (polyoxyethylene (POE) sorbitan mono-hydroxy oleate and POE mono-keto oleate) whose structures were elucidated via nuclear magnetic resonance. A total of 348 (32 types) oxidized species were profiled and identified in the oxidized PS80 samples, including 119 (10 types) species found for the first time to our knowledge. Mathematical models were established and validated based on the good logarithmic relation between the POE degree of polymerization and the relative retention time and used to rapidly discover and identify the oxidized species. A novel strategy was established to profile and identify the PS80 oxidized species based on their retention time, HRMS, and HRMS2 data of the detected peaks using an in-house dataset. Using this strategy, 104 (14 types) and 97 (13 types) oxidized species were identified for the first time in PS80 and its preparations, respectively.

A feasible protocol to profile bile acids in dried blood spots from rats using a UHPLC-MS/MS method combining a surrogate matrix.

Dried blood spot (DBS) sampling is a promising method for microliter blood sample collection with the advantages of convenient transportation, storage and clinical operations. However, it is challenging to develop an analytical protocol to determine endogenous metabolites, such as bile acids (BAs) in DBSs, due to the low-blood-volume character of DBSs and the complex features of filter paper. Herein, we developed a method of fast ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) to profile and quantify BAs in DBSs. The pretreatment methods were optimized and a two-step solvent addition method, where a small amount of water was firstly added to moisten the DBS and then methanol was added, showed high extraction efficiency for multiple BAs in DBSs. The UHPLC-MS/MS conditions were optimized and 35BAs in different types could be profiled with good resolution and quantified with acceptable precision and accuracy. Preparation of a DBS surrogate matrix without endogenous BAs has been well developed using rat erythrocytes in BSA solution and showed good performance on both the signal suppression/enhancement percentage and parallelism assessment evaluation of three different stable-isotope-labeled (SIL) BAs. The established protocol was successfully applied to profile BAs in DBSs of intrahepatic cholestasis model and healthy control rats with good repeatability. To our knowledge, it is the first time that 35 BAs in DBSs could be well profiled and an appropriate DBS surrogate matrix has been developed. This protocol presents future-oriented applications of DBSs for relevant preclinical studies to profile BAs and probe biomarkers.

Efficient expansion of mouse hematopoietic stem cells ex vivo by membrane anchored Angptl2.

Hematopoietic stem cell (HSC) transplantation represents an important curative therapy for numerous hematological and immune diseases. Many efforts have been applied to achieve attainable ex vivo HSC expansion. We previously showed that angiopoietin-like proteins 2 (Angptl2) binds and activates the immune inhibitory receptor human leukocyte immunoglobulin (Ig)-like receptor B2 (LILRB2) to support the expansion of HSC. However, soluble Angptl2 is unstable and the downstream signaling would be attenuated by ligand-binding triggered receptor endocytosis, compromising the potential of Angptl2 to expand HSCs. We proposed that membrane anchored Angptl2 will overcome these limitations. In this study, we constructed the C-terminal and N-terminal anchored membrane Angptl2 (Cm-Angptl2 and Nm-Angptl2) by adding a transmembrane domain at the C-terminal or an anchor sequence at the N-terminal respectively. Both forms of Angptl2 showed efficient expression on the surface of feeder cells. Nm-Angptl2, but not Cm-Angptl2, induces a potent activation of LILRB2 reporter, indicating the fibronectin (FBN) domain at the C-terminus of Angptl2 is essential to stimulate LILRB2 signaling. Compared to soluble Angptl2, Nm-Angptl2 displays higher activities to activate LILRB2 reporter, and to promote the expansion of mouse HSCs as determined by transplantation and limiting dilution assay. Our study revealed the importance of FBN domain for Angptl2 to activate LILRB2 and demonstrated that Nm-Angptl2 have enhanced activities than the soluble protein in LILRB2 activation and HSC expansion, providing a strategy to explore the mode of ligand induced receptor signaling, and an optimized approach to expand HSCs ex vivo.

Bicyclol Alleviates Atherosclerosis by Manipulating Gut Microbiota.

Atherosclerosis (AS) is associated with high morbidity and mortality, thus imposing a growing burden on modern society. Herb-derived bicyclol (BIC) is a versatile bioactive compound that can be used to treat AS. However, its efficacy in AS is not yet described. Here, it is shown that BIC normalizes gut microflora dysbiosis induced by a high fat diet in Apoe(-/-) mice. Metagenome-wide association study analysis verifies that the modulation on carbohydrate-active enzymes and short-chain fatty acid generating genes in gut flora is among the mechanisms. The gut healthiness, especially the gut immunity and integrity, is restored by BIC intervention, leading to improved systemic immune cell dynamic and liver functions. Accordingly, the endothelial activation, macrophage infiltration, and cholesterol ester accumulation in the aortic arch are alleviated by BIC to lessen the plaque onset. Moreover, it is proved that the therapeutic effect of BIC on AS is transmissible by fecal microbiota transplantation. The current study, for the first time, demonstrates the antiatherosclerotic effects of BIC and shows that its therapeutic value can at least partially be attributed to its manipulation of gut microbiota.

Integrating Intact Mass Analysis and Middle-Down Mass Spectrometry Approaches to Effectively Characterize Trastuzumab and Adalimumab Structural Heterogeneity.

Comprehensive characterization of therapeutic monoclonal antibody (mAb) structures is critical for drug development but remains challenging due to the inherent structural heterogeneity. In this study, an integrated strategy has been developed to characterize trastuzumab structural heterogeneity, which has prominent advantages in fast sample preparation with minimal artifacts, and complementary information obtained from intact mass and middle-down analyses. Our methods were all developed on an electron transfer dissociation (ETD)-enabled Q-TOF instrument. As a result, more than 13 structurally different proteoforms were easily identified and quantified through native and denatured intact mass analysis, which may result from the collective differences in glycosylation and C-terminal lysine clipping. Based on collision-induced dissociation and ETD-combined middle-down analysis, sequence coverage values of 28, 45, and 41% for trastuzumab Fc/2, Lc, and Fd subunits, respectively, were reached in a single LC run. The main glycan structure and relative abundance level were determined, and the glycosylation site was confirmed to be on the Fc fragment Asn 61. We finally integrated the native MS and middle-down results to have a more realistic detection of molecular weight, sequence variants, and glycosylation variants of trastuzumab. Applying the integrated strategy, we successfully completed the comprehensive characterization of adalimumab and found unexpected C-terminal lysine-modified variants (dataset identifier PXD021287). Overall, our integration strategy can be easily implemented for in-depth mAb structural heterogeneity characterization during pharmaceutical development and quality control.

A review on analytical methods for pharmaceutical and personal care products and their transformation products.

Pharmaceutical and personal care products (PPCPs) and corresponding transformation products have caused widespread concern due to their persistent emissions and potential toxicity. They have wide octanol-water partition coefficients (Kow) and different ionization constants (pKa) resulting in a poor analysis accuracy and efficiency. A suitable analytical method is the first prerequisite for further research on their environmental behavior to prioritize the substances. This study reviewed a full-scale analytical protocol for environmental samples in the recent ten years: from sampling to instrumental methods. Passive sampling techniques were compared and recommended for long-term continuous and scientific observation. A quick and effective sample extraction and clean-up method are highly required. Chromatographic methods coupled to mass spectrometry for determining PPCPs with a wide range of logKow (-7.53 to 10.80) were summed up. High-resolution mass spectrometry was confirmed to be a promising strategy for screening unknown transformation products, which would provide a nanogram level of detection limits and more accurate mass resolution. Screening strategies and mass change principles were summarized in detail. The recovery rate was important in multiple contaminants analysis identification and factors affecting the recovery rate of PPCPs were also discussed in this review, including sample matrix, target compounds characteristics, extraction method and solid-phase adsorbent. This review provides useful information for the selection of appropriate analytical methods and future development directions.

Profiling of Cholesteryl Esters by Coupling Charge-Tagging Paternò-Büchi Reaction and Liquid Chromatography-Mass Spectrometry.

The profile of cholesteryl esters (CEs) is increasingly used in metabolic disease monitoring due to the roles of CE in regulating the cholesterol level. While electrospray ionization-tandem mass spectrometry is routinely applied for the identification and quantitation of CE, it has a limitation of not being able to provide the location of carbon-carbon double bond (C═C) within unsaturated fatty acyls. In this study, we paired offline 2-acetylpyridine (2-AP) Paternò-Büchi (PB) reaction and reversed-phase liquid chromatography-tandem mass spectrometry to achieve highly sensitive and structural informative CE analysis from complex mixtures. The 2-AP PB reactions of CE standards provided 20-30% conversion but resulted in enhanced ion signal relative to that of intact CE detected as ammonium adduct ions. MS/MS of 2-AP derivatized CE via collision-induced dissociation produced two abundant diagnostic ions for each C═C in a fatty acyl, leading to both sensitive identification and quantitation of C═C location isomers. Twelve saturated and twenty-seven unsaturated CEs were profiled in pooled human plasma; of the latter group, relative quantitation of 6 groups of C═C location isomers was achieved. A dehydrocholesteryl ester, DHE 18:2 (Δ9,12), was confidently differentiated from coexisting compositional isomers: CE 18:3 (Δ9,12,15) and CE 18:3 (Δ6,9,12). The above results represented improved CE coverage at the C═C location level over those reported by gas chromatography MS or acetone PB-MS/MS methods.

Spermine promotes pulmonary vascular remodelling and its synthase is a therapeutic target for pulmonary arterial hypertension.

Pathological mechanisms of pulmonary arterial hypertension (PAH) remain largely unexplored. Effective treatment of PAH remains a challenge. The aim of this study was to discover the underlying mechanism of PAH through functional metabolomics and to help develop new strategies for prevention and treatment of PAH.Metabolomic profiling of plasma in patients with idiopathic PAH was evaluated through high-performance liquid chromatography mass spectrometry, with spermine identified to be the most significant and validated in another independent cohort. The roles of spermine and spermine synthase were examined in pulmonary arterial smooth muscle cells (PASMCs) and rodent models of pulmonary hypertension.Using targeted metabolomics, plasma spermine levels were found to be higher in patients with idiopathic PAH compared to healthy controls. Spermine administration promoted proliferation and migration of PASMCs and exacerbated vascular remodelling in rodent models of pulmonary hypertension. The spermine-mediated deteriorative effect can be attributed to a corresponding upregulation of its synthase in the pathological process. Inhibition of spermine synthase in vitro suppressed platelet-derived growth factor-BB-mediated proliferation of PASMCs, and in vivo attenuated monocrotaline-mediated pulmonary hypertension in rats.Plasma spermine promotes pulmonary vascular remodelling. Inhibiting spermine synthesis could be a therapeutic strategy for PAH.

4,5 caffeoylquinic acid and scutellarin, identified by integrated metabolomics and proteomics approach as the active ingredients of Dengzhan Shengmai, act against chronic cerebral hypoperfusion by regulating glutamatergic and GABAergic synapses.

Dengzhan Shengmai (DZSM) is a proprietary Chinese medicine for remarkable curative effect as a treatment of cerebrovascular diseases, such as chronic cerebral hypoperfusion (CCH) and dementia based on evidence-based medicine, which have been widely used in the recovery period of ischemic cerebrovascular diseases. The purpose of this study was to investigate the active substances and mechanism of DZSM against CCH. Integrative metabolomic and proteomic studies were performed to investigate the neuroprotective effect of DZSM based on CCH model rats. The exposed components of DZSM in target brain tissue were analysed by a high-sensitivity HPLC-MS/MS method, and the exposed components were tested on a glutamate-induced neuronal excitatory damage cell model for the verification of active ingredients and mechanism of DZSM. Upon proteomic and metabolomic analysis, we observed a significant response in DZSM therapy from the interconnected neurotransmitter transport pathways including glutamatergic and GABAergic synapses. Additionally, DZSM had a significant regulatory effect on glutamate and GABA-related proteins including vGluT1 and vIAAT, suggested that DZSM could be involved in the vesicle transport of excitatory and inhibitory neurotransmitters in the pre-synaptic membrane. DZSM could also regulated the metabolism of arachidonic acid (AA), phospholipids, lysophospholipids and the expression of phospholipase A2 in post-synaptic membrane. The results of glutamate-induced neuronal excitatory injury cell model experiment for verification of active ingredients and mechanism of DZSM showed that there are five active ingredients, and among them, 4,5 caffeoylquinic acid (4,5-CQA) and scutellarin (SG) could simultaneously affect the GABAergic and glutamatergic synaptic metabolism as well as the related receptors, the NR2b subunit of NMDA and the α1 subunit of GABAA. The active ingredients of DZSM could regulate the over-expression of the NMDA receptor, enhance the expression of the GABAA receptor, resist glutamate-induced neuronal excitatory damage, and finally maintain the balance of excitatory and inhibitory synaptic metabolism dominated by glutamate and GABA. Furtherly, we compared the efficacy of DZSM, 4,5-CQA, SG and the synergistic effect of 4,5-CQA and SG, and the results showed that all the groups significantly improved cell viability compared with the model group (p < 0.001). The western blot results showed that DZSM, 4,5-CQA, SG and 4,5-CQA/SG co-administration groups could significantly regulate the expression of receptors (GABAA α1 and NR2b subunit of NMDA) and synaptic-related proteins, such as Sv2a, Syp, Slc17a7, bin1 and Prkca, respectively. These results proved DZSM and its active ingredients (4,5-CQA and SG) had the effect of regulating glutamatergic and GABAergic synapses. Finally, membrane potential FLIPR assay of 4,5-CQA and SG was used for GABRA1 activity test, and it was found that the two compounds could increase GABA-induced activation of GABRA1 receptor (GABA 10 µM) in a dose-dependent manner with EC50 value of 48.74 µM and 29.77 µM, respectively. Manual patch clamp method was used to record NMDA NR1/NR2B subtype currents, and scutellarin could cause around 10 % blockade at 10 µM (p＜0.05 compared with the control group). These studies provided definitive clues of the mechanism for the neuroprotective effect of DZSM for CCH treatment and the active compounds regulating glutamatergic and GABAergic synapses. Additionally, 4,5-CQA and SG might be potential drugs for the treatment of neurodegenerative disease related to CCH.

Characterization of pharmaceutic structured triacylglycerols by high-performance liquid chromatography/tandem high-resolution mass spectrometry and its application to structured fat emulsion injection.

RATIONALE: Structured triacylglycerols (STAGs) are a complex mixture of triacylglycerols which are esterified by long-chain fatty acids and medium-chain fatty acids with the same glycerol molecular backbone. As a kind of lipid pharmaceutic excipients, STAGs are used in the pharmaceutical industry as major components of structured fat emulsion injections and play an important role in pharmaceutic energy material because they improve nutritional status with faster elimination in a safe way. The composition and proportion of triacylglycerols in STAGs are closely related to the stability of pharmaceutical preparations and curative effects in the clinic. Therefore, it is necessary to characterize pharmaceutic STAGs using a rapid and accurate method. METHODS: An analytical method for rapid and accurate determination of triacylglycerols in pharmaceutic STAGs was developed using high-performance liquid chromatography/tandem high-resolution mass spectrometry (HPLC/HRMS). Triacylglycerol components could be well separated on a Waters Xterra MS C8 (2.1 × 100 mm, 3.5 µm) column. Four-dimensional HPLC/HRMS data (high-resolution m/z, MS2 data, retention time and isotopic intensity distribution) were used to identify triacylglycerols using Lipid Data Analyzer (LDA) software and the LIPID MAPS database. Then, these identified triacylglycerol components were relatively quantified by their corresponding normalized peak areas using representative standard curves of structurally similar standard substances. RESULTS: Forty-seven kinds of triacylglycerol components in pharmaceutic STAGs and structured fat emulsion injection were identified and relatively quantified by this method. It has been shown that their retention times are in good correlation with the number of carbon atoms and carbon-carbon double bonds. The main components in pharmaceutic STAGs and structured fat emulsion injection were triacylglycerols containing both medium-chain fatty acids and long-chain fatty acids, while the other components, including triacylglycerols containing three medium-chain fatty acids and triacylglycerols containing three long-chain fatty acids, were relatively low. CONCLUSIONS: This study has provided a rapid and accurate approach for the identification and quality control of pharmaceutic STAGs and structured fat emulsion injection and this approach can be extended to other lipid pharmaceutic excipients and used as an effective and reasonable control to guarantee the quality of pharmaceutical preparations.

Recent developments in DNA adduct analysis using liquid chromatography coupled with mass spectrometry.

The formation of DNA adducts by genotoxic agents is an early event in cancer development, and it may lead to gene mutations, thereby initiating tumor development. The measurement of DNA adducts can provide critical information about the genotoxic potential of a chemical and its mechanism of carcinogenesis. In recent decades, liquid chromatography coupled with mass spectrometry has become the most important technique for analyzing DNA adducts. The improvements in resolution achievable with new chromatographic separation techniques coupled with the high specificity and sensitivity and wide dynamic range of new mass spectrometry systems have been used for both qualitative and quantitative analyses of DNA adducts. This review discusses the challenges in qualitative and quantitative analyses of DNA adducts by liquid chromatography coupled with mass spectrometry and highlights recent developments towards overcoming the limitations of liquid chromatography coupled with mass spectrometry methods. The key steps and new solutions, such as sample preparation, mass spectrometry fragmentation, and method validation, are summarized. In addition, the fundamental principles and latest advances in DNA adductomic approaches are reviewed.

Mathematical Model-Assisted UHPLC-MS/MS Method for Global Profiling and Quantification of Cholesteryl Esters in Hyperlipidemic Golden Hamsters.

Cholesteryl esters (CEs) are formed by the 3-hydroxyl group of cholesterol and a fatty acyl chain through an ester bond and function as a biologically inert storage form of cholesterol. Abnormal CE levels are often related to various diseases, particularly hyperlipidemia and atherosclerosis. Herein, we developed a mathematical model-assisted ultrahigh performance liquid chromatography-mass spectrometry (UHPLC-MS) method for the untargeted identification to targeted quantification of CEs in plasma, different density lipoprotein samples from humans, rats, and golden hamsters. Using UHPLC-quadrupole-time-of-flight mass spectrometry (UHPLC-QTOF-MS), 81 CE candidates were detected in the above samples, of which 24 CEs were reported in the Human Metabolome Database and 57 CEs were newly identified based on an in-house database of theoretically possible CEs, including the computationally generated precursor ion m/ z mass of CE, carbon number and double bond numbers of the fatty acyl chain. Then three mathematical models based on the characteristic chromatographic retention behavior related to structural features were established and validated using commercial and synthetic CE standards. The mathematical model-assisted UHPLC-MS/MS strategy was proposed to provide a global profiling and identification of CEs, especially unknown CEs. With the efficient strategy, 74 CEs in the plasma of golden hamsters were identified and then quantified in normal and hyperlipidemic golden hamsters by dynamic multiple reaction monitoring (dMRM). A total of 21 CEs among 35 shared potential biomarkers were newly found for hyperlipidemia. Our work will contribute to the in-depth study of the functions of CEs and the discovery of disease biomarkers.

Genetic control of fatty acid composition in coconut (Cocos nucifera), African oil palm (Elaeis guineensis), and date palm (Phoenix dactylifera).

MAIN CONCLUSION: Predominant gene isoforms and expression bias in lipid metabolism pathways are highly conserved between oil-producing Arecaceae crop species coconut and oil palm, but diverge in non-oil-producing species date palm. Coconut (Cocos nucifera), African oil palm (Elaeis guineensis) and date palm (Phoenix dactylifera) are three major crop species in the Arecaceae family for which genome sequences have recently become available. Coconut and African oil palm both store oil in their endosperms, while date palm fruits contain very little oil. We analyzed fatty acid composition in three coconut tissues (leaf, endosperm and embryo) and in two African oil palm tissues (leaf and mesocarp), and identified 806, 840 and 848 lipid-related genes in 22 lipid metabolism pathways from the coconut, African oil palm and date palm genomes, respectively. The majority of lipid-related genes were highly homologous and retained in homologous segments between the three species. Genes involved in the conversion of pyruvate to fatty acid had a five-to-sixfold higher expression in the coconut endosperm and oil palm mesocarp than in the leaf or embryo tissues based on Fragments Per Kilobase of transcript per Million mapped reads values. A close evolutionary relationship between predominant gene isoforms and high conservation of gene expression bias in the lipid and carbohydrate gene metabolism pathways was observed for the two oil-producing species coconut and oil palm, differing from that of date palm, a non-oil-producing species. Our results elucidate the similarities and differences in lipid metabolism between the three major Arecaceae crop species, providing important information for physiology studies as well as breeding for fatty acid composition and oil content in these crops.

A UPLC/MS/MS method for comprehensive profiling and quantification of fatty acid esters of hydroxy fatty acids in white adipose tissue.

Fatty acid esters of hydroxy fatty acids (FAHFAs) are recently discovered lipids with antidiabetic and anti-inflammatory effects. We have developed an ultrahigh-performance liquid chromatography (UPLC) coupled with tandem mass spectrometry (MS) method for comprehensive profiling and quantification of FAHFAs. Through optimization of the chromatographic conditions, most FAHFA isomers can be efficiently separated and quantified in 29 min with excellent peak shape and good robustness. UPLC coupled with quadrupole time-of-flight (Q-TOF) MS was used for identification of FAHFAs based on the high-resolution m/z values and the fragmentation rules. Sixty-four FAHFAs, belonging to 17 different families, were identified in white adipose tissue (WAT) of golden hamsters. Nine of the 17 FAHFA family members were newly discovered in this work, and linoleic acid and linolenic acid were newly found fatty acid moieties of FAHFAs. The total number of FAHFAs identified from WAT in this work is far larger than that in any previously reported work. The parameters (precursor ions, product ions, and collision energy) of the 64 FAHFAs identified in golden hamster WAT by UPLC/Q-TOF-MS were further used in UPLC coupled with triple-quadrupole (QQQ) MS for quantification in multiple reaction monitoring mode. Finally, this newly developed UPLC/QQQ-MS method was used for the quantification of FAHFAs in hamster WAT attached to epididymis, kidney, intestine, and inguen to explore the disturbance of the levels of WAT FAHFAs in the pathological state of hyperlipidemia. The regulation effects of fenofibrate on the levels of WAT FAHFAs were also investigated. The results show that fenofibrate therapy can increase the concentration of FAHFAs in WAT. Graphical abstract ᅟ.

Mass-spectrometry-based lipidomics.

Lipids, which have a core function in energy storage, signalling and biofilm structures, play important roles in a variety of cellular processes because of the great diversity of their structural and physiochemical properties. Lipidomics is the large-scale profiling and quantification of biogenic lipid molecules, the comprehensive study of their pathways and the interpretation of their physiological significance based on analytical chemistry and statistical analysis. Lipidomics will not only provide insight into the physiological functions of lipid molecules but will also provide an approach to discovering important biomarkers for diagnosis or treatment of human diseases. Mass-spectrometry-based analytical techniques are currently the most widely used and most effective tools for lipid profiling and quantification. In this review, the field of mass-spectrometry-based lipidomics was discussed. Recent progress in all essential steps in lipidomics was carefully discussed in this review, including lipid extraction strategies, separation techniques and mass-spectrometry-based analytical and quantitative methods in lipidomics. We also focused on novel resolution strategies for difficult problems in determining C=C bond positions in lipidomics. Finally, new technologies that were developed in recent years including single-cell lipidomics, flux-based lipidomics and multiomics technologies were also reviewed.

Toxicokinetics of strychnine and brucine after the oral administration of Biqi capsule to rats by RRLC-MS/MS.

Biqi capsule is a well-known traditional Chinese medicine formula that has been widely applied for the clinical treatment of such diseases as rheumatoid arthritis, scapulohumeral periarthritis and cervical spondylopathy. However, there is concern regarding the toxicity of Biqi capsule owing to its active ingredients, strychnine and brucine. To investigate the toxicokinetics of strychnine and brucine after oral administration of Biqi capsule to rats, a sensitive and simple rapid-resolution liquid chromatography/tandem mass spectrometry method was developed to determine the levels of strychnine and brucine in rat plasma. Chromatographic separation was performed on a Capcell Pak C18 MG II (3.0 µm, 2.0 × 35 mm) column by gradient elution with acetonitrile and 0.2% formic acid as the mobile phase. The method was validated over the range of 0.25-250 ng/mL for strychnine and 0.025-25 ng/mL for brucine. The intra- and inter-day accuracies of strychnine and brucine in rat plasma were 100.3-106.6 and 90.75-106.1% respectively, and the precisions were within 14.2%. The established method was successfully applied to the toxicokinetic study of strychnine and brucine after single and multiple oral administration of Biqi capsule to male and female rats at 0.4, 0.8 and 1.6 g/kg doses. The results showed different toxicokinetic characteristics in the different groups.