Effect of lysophosphatidylglycerol on intracellular free Ca2+ concentration in A10 vascular smooth muscle cells

Lipidomic changes in the liver of beagle dogs associated with Toxocara canis infection

A global lipidomic analysis using liquid chromatography–tandem mass spectrometry was performed on the liver of beagle dogs infected with Toxocara canis to profile hepatic lipid species at 12 h post-infection (hpi), 24 hpi, and 36 days post-infection (dpi). This analysis identified six categories and 42 subclasses of lipids, including 173, 64, and 116 differentially abundant lipid species at 12 hpi, 24 hpi, and 36 dpi, respectively. Many of the identified lysophospholipids, such as lysophosphatidylglycerol, lysophosphatidylserine, and lysophosphatidylcholine, may contribute to the migration and development of T. canis during the early infection stage. Pathway analysis revealed significant alterations of several immune-inflammatory pathways, such as the B-cell receptor signaling pathway, the NF-kappa B signaling pathway, and the C-type lectin receptor signaling pathway at 12 and 24 hpi. These findings demonstrate the value of lipidomic profiling in revealing the extent of changes in the composition and abundance of hepatic lipidome caused by T. canis infection and their relevance to the pathophysiology of toxocariasis in beagle dogs.

Analysis of the aqueous humor lipid profile in patients with polypoidal choroidal vasculopathy

This study aimed to investigate the lipid profiles of aqueous humor from polypoidal choroidal vasculopathy (PCV) patients and identify potential biomarkers to increase the understanding of PCV pathomechanism. An ultra-high performance liquid chromatography-tandem mass spectrometry based untargeted lipidomic analysis was performed to acquire lipid profiles of aqueous humor of PCV patients and control subjects. Differentially expressed lipids were identified by univariate and multivariate analyses. A receiver operator characteristic curve (ROC) analysis was conducted to confirm the potential of identified lipids as biomarkers. Sixteen PCV patients and twenty-eight control subjects were enrolled in this study. In total, we identified 33 lipid classes and 639 lipid species in aqueous humor using the LipidSearch software. Of them, 50 differential lipids were obtained by combining univariate and multivariate statistical analyses (VIP>1 and P < 0.05), and 19 potential lipid biomarkers were identified by ROC analysis. In addition, significant alterations were found in several metabolic pathways, including glycerophospholipid, glycerolipid, and glycosylphosphatidylinositol-anchor biosynthesis. This study is the first to systematically characterize the alterations in lipid profiles in aqueous humor of PCV patients and screen for the potential lipid biomarkers for PCV diagnosis and treatment intervention. The results of this study are likely to broaden our understanding of the pathogenesis of PCV and contribute to improvements in the diagnosis and treatment of the disease.

Detoxification modification of coal-tar pitch by ultraviolet & microwave radiation-enhanced chemical reaction and toxicity evaluation by chemical index and cytotoxicity assay in vitro

Although coal tar pitch (CTP) has a large yield in China, its large-scale and effective utilization is significantly hindered because of existing and possibly releasing polycyclic aromatic hydrocarbons (PAHs). Therefore, it is an imminent problem how to prepare an environmentally friendly CTP by detoxification modification. In the investigation, a typical CTP was subjected to structural characterization via solid-state ¹³C NMR and gas chromatograph/mass spectrometer, which confirmed the existence of dominant PAHs such as fluoranthene, pyrene, as well as benzo[a]pyrene, and few heterocyclic compounds. Subsequently, the CTP was modified using 10-undecenal via alkylation reaction enhanced by ultraviolet & microwave radiation. Compared with the original CTP, the total content of 16 toxic PAHs in the modified CTP decreased with a reduction efficiency of above 90%. According to different environmental standards, toxic equivalent quotient of CTP after modification was reduced by above 90%. In order to veritably and fully evaluate the toxicity of CTP, a living vascular smooth muscle cell (A-10 cell) in vitro was used in the cell counting kit-8 assay. The viability of A-10 cell was always higher when exposed to modified CTP than the original CTP. These results powerfully indicated that the enhanced modification was actually effective and efficient for reducing the toxicity of CTP.

Metabolic alterations in the erythrocyte during blood-stage development of the malaria parasite

Background

Human blood cells (erythrocytes) serve as hosts for the malaria parasite Plasmodium falciparum during its 48-h intraerythrocytic developmental cycle (IDC). Established in vitro protocols allow for the study of host–parasite interactions during this phase and, in particular, high-resolution metabolomics can provide a window into host–parasite interactions that support parasite development.

Methods

Uninfected and parasite-infected erythrocyte cultures were maintained at 2% haematocrit for the duration of the IDC, while parasitaemia was maintained at 7% in the infected cultures. The parasite-infected cultures were synchronized to obtain stage-dependent information of parasite development during the IDC. Samples were collected in quadruplicate at six time points from the uninfected and parasite-infected cultures and global metabolomics was used to analyse cell fractions of these cultures.

Results

In uninfected and parasite-infected cultures during the IDC, 501 intracellular metabolites, including 223 lipid metabolites, were successfully quantified. Of these, 19 distinct metabolites were present only in the parasite-infected culture, 10 of which increased to twofold in abundance during the IDC. This work quantified approximately five times the metabolites measured in previous studies of similar research scope, which allowed for more detailed analyses. Enrichment in lipid metabolism pathways exhibited a time-dependent association with different classes of lipids during the IDC. Specifically, enrichment occurred in sphingolipids at the earlier stages, and subsequently in lysophospholipid and phospholipid metabolites at the intermediate and end stages of the IDC, respectively. In addition, there was an accumulation of 18-, 20-, and 22-carbon polyunsaturated fatty acids, which produce eicosanoids and promote gametocytogenesis in infected erythrocyte cultures.

Conclusions

The current study revealed a number of heretofore unidentified metabolic components of the host–parasite system, which the parasite may exploit in a time-dependent manner to grow over the course of its development in the blood stage. Notably, the analyses identified components, such as precursors of immunomodulatory molecules, stage-dependent lipid dynamics, and metabolites, unique to parasite-infected cultures. These conclusions are reinforced by the metabolic alterations that were characterized during the IDC, which were in close agreement with those known from previous studies of blood-stage infection.

Lysophospholipases cooperate to mediate lipid homeostasis and lysophospholipid signaling

Lysophospholipids (LysoPLs) are bioactive lipid species involved in cellular signaling processes and the regulation of cell membrane structure. LysoPLs are metabolized through the action of lysophospholipases, including lysophospholipase A1 (LYPLA1) and lysophospholipase A2 (LYPLA2). A new X-ray crystal structure of LYPLA2 compared with a previously published structure of LYPLA1 demonstrated near-identical folding of the two enzymes; however, LYPLA1 and LYPLA2 have displayed distinct substrate specificities in recombinant enzyme assays. To determine how these in vitro substrate preferences translate into a relevant cellular setting and better understand the enzymes' role in LysoPL metabolism, CRISPR-Cas9 technology was utilized to generate stable KOs of Lypla1 and/or Lypla2 in Neuro2a cells. Using these cellular models in combination with a targeted lipidomics approach, LysoPL levels were quantified and compared between cell lines to determine the effect of losing lysophospholipase activity on lipid metabolism. This work suggests that LYPLA1 and LYPLA2 are each able to account for the loss of the other to maintain lipid homeostasis in cells; however, when both are deleted, LysoPL levels are dramatically increased, causing phenotypic and morphological changes to the cells.

Mass isotopomer-guided decluttering of metabolomic data to visualize endogenous biomarkers of drug toxicity

Metabolomics offers the opportunity to uncover endogenous biomarkers that can lead to metabolic pathways and networks and that underpin drug toxicity mechanisms. A novel protocol is presented and discussed that is applicable to drugs which generate urinary metabolites when administered to mice sensitive to its toxicity. The protocol would not apply to drugs that are not metabolized or eliminated by a different route. Separate stable isotope-labeled and unlabeled drug administration to mice is made together with collection of urines from control animals. Untargeted mass spectrometry-based metabolomic analysis of these three urine groups is conducted in addition to principal components analysis (PCA). In the case of unlabeled acetaminophen and [acetyl-²H₃]acetaminophen, each given at a hepatotoxic dose (400 mg/kg i.p.) to the sensitive mouse strain (wild-type 129), the PCA loadings plot showed a distribution of ions in the shape of a "fallen-Y" with the deuterated metabolites in one arm and the paired nondeuterated metabolites in the other arm of the fallen-Y. Ions corresponding to the endogenous toxicity biomarkers sat in the mouth of the fallen-Y. This protocol represents an innovative means to separate endogenous biomarkers from drug metabolites, thereby aiding the identification of biomarkers of drug toxicity. For acetaminophen, increased hepatic oxidative stress, mitochondrial damage, Ca²⁺ signaling, heme catabolism, and saturation of glucuronidation, together with decreased fatty acid β-oxidation and cellular energy dysregulation were all implied from the discovered biomarkers. The protocol can be applied to other drugs and may now be translated to clinical studies.