Exogenous phosphatidylethanolamine induces apoptosis of human hepatoma HepG2 cells via the bcl-2/bax pathway

AIM: To investigate the signaling pathways implicated in phosphatidylethanolamine (PE)-induced apoptosis of human hepatoma HepG2 cells. METHODS: Inhibitory effects of PE on human hepatoma HepG2 cells were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell cycle, apoptosis and mitochondrial transmembrane potential (ΔΨm) were analyzed by flow cytometry. Immunocytochemical assay and Western blotting were used to examine Bcl-2, Bax and caspase-3 protein levels in HepG2 cells treated with PE. RESULTS: PE inhibited the growth of HepG2 cells in a doseand timedependent manner. It did notaffect the cell cycle, but induced apoptosis. PE significantly decreased ΔΨm at 0.25, 0.5 and 1 mmol/L, respectively, suggesting that PE induces cell apoptosis by decreasing the mitochondrial transmembrane potential. The Bcl-2 expression level induced by different concentrations of PE was lower than that in control groups. However, the Bax expression level induced by PE was higher than that in the control group. Meanwhile, PE increased the caspase-3 expression in a doseand time-dependent manner. CONCLUSION: Exogenous PE induces apoptosis of human hepatoma HepG2 cells via the bcl-2/bax pathway.

Phosphatidylethanolamine N-methyltransferase and choline dehydrogenase gene polymorphisms are associated with human sperm concentration

Choline is a crucial factor in the regulation of sperm membrane structure and fluidity, and this nutrient plays an important role in the maturation and fertilizing capacity of spermatozoa. Transcripts of phosphatidylethanolamine N-methyltransferase （PEMT） and choline dehydrogenase （CHDH）, two basic enzymes of choline metabolism, have been observed in the human testis, demonstrating their gene expression in this tissue. In the present study, we explored the contribution of the PEMTand CHDHgene variants to sperm parameters. Two hundred oligospermic and 250 normozoospermic men were recruited. DNA was extracted from the spermatozoa, and the PEMT -774G〉C and CHDH ＋432G〉T polymorphisms were genotyped. The genotype distribution of the PEMT-774G〉C polymorphism did not differ between oligospermic and normozoospermic men. In contrast, in the case of the CHDH ＋432G〉T polymorphism, oligospermic men presented the CHDH432GIG genotype more frequently than normozoospermic men （62% vs. 42%, P〈0.001）. The PEMT774GIG genotype was associated with a higher sperm concentration compared to the PEMT774GIC and 774C/C genotypes in oligospermic men （12.5±5.6× 10^6 spermatozoa m1-1 vs. 8.3±5.2×10^6 spermatozoa m1-1, P〈0.002） and normozoospermic men （81.5±55.6×10^6 vs. 68.1±44.5×10^6 spermatozoa m1-1, P〈0.006）. In addition, the CHDH432G/G genotype was associated with higher sperm concentration compared to CHDH432G.T and 432T/T genotypes in oligospermic （11.8±5.1×10^6 vs. 7.8±5.3×10^6 spermatozoa m1-1, P〈0.003） and normozoospermic men （98.6±62.2×10^6 vs. 58.8±＋33.6×10^6 spermatozoa m1-1, P〉0.001）. In our series, the PEMT-774G〈C and CHDH ＋432G〈T polymorphisms were associated with sperm concentration. This finding suggests a possible influence of these genes on sperm quality.

Phosphatidylethanolamine functionalized biomimetic monolith for immobilized artificial membrane chromatography

In this research,a new phospholipid based monolith was fabricated by in situ co-polymerization of 1-dodecanoyl-2-(11-methacrylamidoundecanoyl)-sn-glycero-3-phosphoethanolamine and ethylene dimethacrylate to mimick bio-membrane environment.Excellent physicochemical properties of this novel monolith that were achieved included column efficiency,stability,and permeability.Moreover,the biomimetic monolith showed outstanding separation capability for a series of intact proteins and small molecules.In particular,it exhibited good potential as an alternative to the commercial immobilized artificial membrane(IAM)column(IAM.PC.DD2)for studying drug-membrane interactions.This study not only enriched the types of IAM stationary phases,but also provided a simple model for the prediction of phosphatidylethanolamine related properties of drug candidates.

A Comparative Study About the Neuroprotective Effects of EPA-Enriched Phosphoethanolamine Plasmalogen and Phosphatidylethanolamine Against Oxidative Damage in Primary Hippocampal Neurons

s Oxidative stress is involved in the progression of neurodegenerative diseases.Previous evidences showed that plasma-logens could improve neurodegenerative diseases.In this study,we investigated the function of phosphoethanolamine plasmalogens enriched with EPA(EPA-pPE)and phosphatidylethanolamine enriched with EPA(EPA-PE)on oxidative damage prevention after hy-drogen peroxide(H2O2)and tert-butylhydroperoxide(t-BHP)challenge in primary hippocampal neurons.Results showed that neurons pretreated with EPA-pPE and EPA-PE demonstrated the ability to alleviate oxidative damage,which was proved by the in-creased cell viability.Moreover,the shape and number of neurons were more similar to those of the control group.Antioxidant acti-vity,apoptosis,as well as TrkB/ERK/CREB signaling pathway were investigated to explore the mechanisms.The results suggested that EPA-PE was superior to EPA-pPE in regulating mitochondrial apoptosis.EPA-pPE was more prominent than EPA-PE in upre-gulating TrkB/ERK/CREB signaling pathway.Phospholipids with EPA exerted neuroprotective effects via inhibiting oxidative stress,suppressing apoptosis,and regulating TrkB/ERK/CREB signaling pathway.Therefore,the results provide a scientific basis for utili-zation of phospholipids enriched with EPA on the treatment of neurodegenerative disease.

A new synthetic approach to phosphatidylethanolamine

A new synthetic method for phosphatidylethanolamine head group was developed via ring-opening of cyclic dioxaphospholane 2 with sodium azide and subsequent hydrogenation.The advantage of this strategy included short reaction steps,readily available materials and good yields.

Rapid chromatographic method to decipher distinct alterations in lipid classes in NAFLD/NASH

AIM: To establish a simple method to quantify lipid classes in liver diseases and to decipher the lipid profile in p62/IMP2-2/IGF2BP2-2 transgenic mice.METHODS: Liver-specific overexpression of the insulin-like growth factor 2 mRNA binding protein p62/IMP2-2/IGF2BP2-2 was used as a model for steatosis.Steatohepatitis was induced by feeding a methioninecholine deficient diet. Steatosis was assessed histologically. For thin layer chromatographic analysis, lipids were extracted from freeze-dried tissues by hexane/2-propanol, dried, redissolved, and chromatographically separated by a two-solvent system. Dilution series of lipid standards were chromatographed, detected, andquantified. The detection was performed by either2',7'-dichlorofluoresceine or a sulfuric acid/ethanol mixture.RESULTS: Histological analyses confirmed steatosis and steatohepatitis development. The extraction,chromatographic, and detection method showed high inter-assay reproducibility and allowed quantification of the different lipid classes. The analyses confirmed an increase of triglycerides and phosphatidylethanolamine and a decrease in phosphatidylcholine in the methionine-choline deficient diet. The method was used for the first time to asses the lipid classes induced in the p62-overexpressing mouse model and showed a significant increase in all detected lipid species with a prominent increase of triglycerides by 2-fold. Interestingly, the ratio of phosphatidylcholine to phosphatidylethanolamine was decreased, as previously suggested as a marker in the progression from steatosis to steatohepatitis.CONCLUSION: The thin layer chromatography analysis allows a reliable quantification of lipid classes and provides detailed insight into the lipogenic effect of p62.

Analysis of Phospholipids in Crucian Carp(Carassius auratus) Muscle by Offline HPLC-MALDI-TOF MS

The interest in the analysis of phospholipids(PLs), especially phosphatidylcholine(PC), has been increasing due to the importance of them in biochemistry as well as in industry. A method was reported based on the offline combination of MALDI-TOF MS and normal-phase HPLC for analyzing PLs extracted from crucian carp. Total PLs of crucian carp were extracted and then separated by HPLC before the collected subfractions were analyzed by MALDI-TOF MS. The mass spectra obtained show peaks of H+, Na+ and K+ adducts of PC molecules. It is shown that the prior separation of PLs by HPLC is highly necessary to remove the signal suppressing and to avoid the possible overlapping. With this method, 9 possible PC molecules in crucian carp and the corresponding fatty acid compositions were given from the well-resolved mass spectra.

Interaction of <i>Helicobacter pylori</i>Cell Membrane with Non-Esterified Cholesterol and Other Steroids

Helicobacter pylori performs the unique action of assimilating exogenous non-esterified cholesterol into its cell membrane. This bacterium aggressively incorporates non-esterified cholesterol into the membrane, induces its glucosylation, and uses both non-esterified cholesterol and glucosylated cholesterols as membrane lipid compositions. The reason for this assimilation of non-esterified cholesterol into the cell membrane of H. pylori has eluded investigators for many years. Recent hypotheses posit that the sterol-uptake and sterol-glucosylation contribute to the survival of H. pylori cells in different ways. The incorporation of the non-esterified cholesterol into the cell membrane fortifies the resistance of H. pylori against the antibacterial actions of phosphatidylcholines, antibiotics, and bile salts. In parallel, the glucosylation of the non-esterified cholesterol incorporated into the cell membrane serves H. pylori in two ways. First, it helps the bacterium evade host immune responses, such as phagocytosis by macrophages and activation of antigen-specific T cells. Second, it detoxifies sterols fatal to the bacterium via a novel action of sterol glucosylation recently described in another report from our group. The reluctance of H. pylori to absorb esterified cholesterol remains unexplained. A recent study by our group has demonstrated that the phosphatidylethanolamine (PE) in the outer membrane of H. pylori serves as a steroid-binding lipid the incorporation of non-esterified cholesterol into the membrane. We have also discovered that the myristic acid (C14:0) molecule attached to the PE of this bacterium plays an important role in the selective binding of non-esterified cholesterol but not esterified cholesterol.

DSC study of phase transitions of cephalin pseudo-binary systems in excess water

The gel-liquid crystal phase transitions of the pseudo-binary systems of cephalins DMPE and DHPE in excess water were studied by differential scanning calorimetry. The phase diagram of the pseudebinary systems has been given. The experiments showed that the partial phase separation in gel phase might occur at least at the mole fractions of DHPE below 0.1. The analysis by the model of ideal solution showed that both the cephalins were non-ideally miscible both in the gel phases and in the liquid crystal phases. The analysis by the model of regular solution showed that all the non-ideality parameters in the gel phases were larger than those in the liquid crystal phases at the same temperature. All the non-ideality parameters were not constant, but rather dependent on temperature.

Plasma Lipidomic Subclasses and Risk of Hypertension in Middle-Aged and Elderly Chinese

While disrupted lipid metabolism is a well-established risk factor for hypertension in animal models,the links between various lipidomic signatures and hypertension in human studies remain unclear.We aimed to examine associations between plasma lipidomic profiles and prevalence of hypertension among 2248 community-living Chinese aged 50-70 years.Hypertension was defined according to 2020 International Society of Hypertension global hypertension practice guidelines and 2018 Chinese guidelines.In total,728 plasma lipidomic species were profiled using high-coverage targeted lipidomics.After multivariate adjustment,including lifestyle,body mass index,blood lipids,and sodium intake,110 metabolites from nine lipidomic subclasses showed significant associations with hypertension,among which phosphatidylethanolamines(PEs)had the strongest association.Eleven lipidomic signals for hypertension risk were further identified from the nine subclasses,including PE(18:0/18:2)(OR per SD,1.49;95%confidence intervals,1.30-1.69),phosphatidylcholine(PC)(18:0/18:2)(1.27;1.13-1.43),phosphatidylserine(18:0/18:0)(1.24;1.09-1.41),lysophosphatidylinositol(18:1)(1.17;1.06-1.29),triacylglycerol(52:5)(1.38;1.18-1.61),diacylglycerol(16:0/18:2)(1.42;1.19-1.69),dihydroceramide(24:0)(1.25;1.09-1.43),hydroxyl-sphingomyelins(SM[2OH])C34:1(1.19;1.07-1.33),lysophosphatidylcholine(20:1)(0.86;0.78-0.95),SM(OH)C38:1(0.87;0.79-0.96),and PC(18:2/20:1)(0.84;0.75-0.94).Principal component analysis also showed that a factor mainly containing specific PEs was positively associated with hypertension(1.20;1.09-1.33).Collectively,our study revealed that disturbances in multiple circulating lipidomic subclasses and signatures,especially PEs,were significantly associated with the prevalence of hypertension in middle-aged and elderly Chinese.Future studies are warranted to confirm our findings and determine the mechanisms underlying these associations.