Blockage of Wnt/β‐Catenin Signaling by Nanoparticles Reduces Survival and Proliferation of CLL Cells In Vitro—Preliminary Study

The Wnt/β‐catenin signaling pathway is shown to play a significant role in the control of the survival, proliferation, and differentiation of hematopoietic cells. Studies have confirmed that aberrant activation of canonical Wnt signaling occurs in various forms of leukemia, and is crucial for chronic lymphocytic leukemia (CLL) pathogenesis. The aim of the study is to evaluate the influence of maltotriose (M3) modified fourth generation poly(propylene imine) dendrimers (PPI‐G4) on Wnt/β‐catenin pathway gene expression in CLL (MEC‐1) cells and to compare these findings with those obtained with fludarabine (FA). Microarray data analysis reveals seven of 19 Wnt/β‐catenin pathway genes whose expression changes significantly during dendrimer and FA treatment: WNT10A, WNT6 , and CDH1 among others. PPI‐G4‐M3 is already known to influence MEC‐1 cell apoptosis and proliferation. The obtained results suggest that the reduction in cell survival under the influence of glycodendrimers and FA may be due to loss of Wnt signaling.     

Fragmentation studies of pentacoordinated bisaminoacylspirophosphoranes by negative electrospray ionization mass spectrometry

Fragmentation pathways of a series of pentacoordinated bisaminoacylspirophosphoranes were elucidated by electrospray ionization multistage mass spectrometry (ESI-MS(n)) in negative mode. The deprotonated ions of pentacoordinated bisaminoacylspirophosphoranes tend to eliminate a corresponding amino acid to form base peak. The hydrogen/deuterium exchange experiment, the high-resolution mass spectrometry, (13)C stable isotope labeling experiment and theoretical calculations were used to rationalize the proposed fragmentation pathways and to verify the differences between the fragmentation pathways. The results indicate that the negative molecular ions of pentacoordinated bisaminoacylspirophosphoranes dissociate through its open-chain tricoordinated tautomers. The relative Gibbs free energies (ΔG) of the product ions and proposed fragmentation pathways were estimated using the B3LYP/6-31 + + G(d, p) model. The results have some potential applications in the identification structures of similar spirophosphorane compounds by ESI-MS(n).     

A Study on bioactivity of Corn Peptides with Low Molecular Weight（Ⅰ）——Effect of an Intake of them on Alcohol Metabolism in Rats

IntroductionIn the past few years,some researchers foundthat small peptides derived from the hydrolysate offood protein play an important role in regulatingautonomic nervous system,activating the cellularimmunity function,ameliorating the cardiovascularfunction,antioxidizng and antaging,etc.[1— 8] .Par-tial proteolysis is effective for improving the func-tional properties of protein.Small peptides havesome advantages compared to protein,such as lowosmotic pressure,fast absorption,good taste a…     

Lipophilicity in PK design: methyl, ethyl, futile

Lipophilicity, often expressed as distribution coefficients (log D) in octanol/water, is an important physicochemical parameter influencing processes such as oral absorption, brain uptake and various pharmacokinetic (PK) properties. Increasing log D values increases oral absorption, plasma protein binding and volume of distribution. However, more lipophilic compounds also become more vulnerable to P450 metabolism, leading to higher clearance. Molecular size and hydrogen bonding capacity are two other properties often considered as important for membrane permeation and pharmacokinetics. Interrelationships among these physicochemical properties are discussed. Increasing size (molecular weight) often gives higher potency, but inevitably also leads to either higher lipophilicity, and hence poorer dissolution/solubility, or to more hydrogen bonding capacity, which limits oral absorption. Differences in optimal properties between gastrointestinal absorption and uptake into the brain are addressed. Special attention is given to the desired lipophilicity of CNS drugs. In examples using -blockers, Ca channel antagonists and peptidic renin inhibitors we will demonstrate how potency and pharmacokinetic properties need to be balanced.     

A UPLC‐TOF/MS‐based metabolomics study of rattan stems of Schisandra chinensis effects on Alzheimer's disease rats model

A UPLC‐TOF/MS‐based metabolomics method was established to explore the therapeutic mechanisms of rattan stems of S. chinensis (SCS) in Alzheimer's disease (AD). Experimental AD model was induced by intra‐hippocampal Aβ_1–42 injection in rats. Cognitive function and oxidative stress condition in brain of AD rats were assessed using Morris water maze tests and antioxidant assays [malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH‐Px)], respectively. UPLC‐TOF/MS combined with multivariate statistical analysis were conducted to study the changes in metabolic networks in serum of rats. The results indicated that the AD model was established successfully and the inducement of Aβ_1–42 caused a decline in spatial learning and memory of rats. The injection of Aβ_1–42 in rat brains significantly elevated the level of MDA, and reduced SOD and GSH‐Px activities. In addition, SCS showed significant anti‐AD effects on model rats. A total of 30 metabolites were finally identified as potential biomarkers of AD and 14 of them had a significant recovery compared with the AD model after SCS administration. Changes in AD metabolite profiling were restored to different levels through the regulation of 13 pathways. This is first report on the use of the UPLC‐TOF/MS‐based serum metabolomics method to investigate therapeutic effects of SCS on AD, and enrich potential biomarkers and metabolic networks of AD.     

Anti‐inflammatory activities and glycerophospholipids metabolism in KLA‐stimulated RAW 264.7 macrophage cells by diarylheptanoids from the rhizomes of Alpinia officinarum

Alpinia officinarum is used for its anti‐inflammatory activity historically in China. Diarylheptanoids isolated from A. officinarum play important biological roles in the prevention and treatment of inflammatory disorders. Seven diarylheptanoids (1–7) were isolated from A. officinarum. The cell viabilities and anti‐inflammatory activities of diarylheptanoids were evaluated by MTT assay and tumor necrosis factor‐α production in Kdo2‐lipid A‐stimulated RAW 264.7 cells in vitro. The relationships between their anti‐inflammatories and structure‐activities are discussed. The results indicated that compounds 1 and 3–7 had significant anti‐inflammatory activities. The relationships between inflammation and phospholipids metabolism were elucidated by multivariate data analysis. Twenty‐two potential biomarkers were identified in inflammatory group vs. blank group, and 11 potential biomarkers were identified for inflammatory group vs. drug‐treatment groups. Ten common phospholipids were characterized. On the basis of a previous study in our laboratory, we found that phosphatidylethanolamine (18:0/18:1) might be the important glycerophospholipid biomarker in inflammation. In this study, we firstly combined anti‐inflammatory activities and glycerophospholipids changes of traditional Chinese medicine. This work suggests that the anti‐inflammatory activities of diarylheptanoids might be significantly related to glycerophospholipids and could provide a useful database for investigating the anti‐inflammatory effects of traditional Chinese medicine.     

Characterization of complex,heterogeneous lipid A samples using HPLC‐MS/MS technique III. Positive‐ion mode tandem mass spectrometry to reveal phosphorylation and acylation patterns of lipid A

In this study, we report the detailed analysis of the fragmentation patterns of positively charged lipid A species based on their tandem mass spectra obtained under low‐energy collision‐induced dissociation conditions of an electrospray quadrupole time‐of‐flight mass spectrometer. The tandem mass spectrometry experiments were performed after the separation of the compounds with a reversed‐phase high performance liquid chromatography method. We found that both, phosphorylated and nonphosphorylated lipid A molecules can be readily ionized in the positive‐ion mode by adduct formation with triethylamine added to the eluent. The tandem mass spectra of the lipid A triethylammonium adduct ions showed several product ions corresponding to inter‐ring glycosidic cleavages of the sugar residues, as well as consecutive and competitive eliminations of fatty acids, phosphoric acid, and water following the neutral loss of triethylamine. Characteristic product ions provided direct information on the phosphorylation site(s), also when phosphorylation isomers (ie, containing either a C1 or a C4′ phosphate group) were simultaneously present in the sample. Continuous series of high‐abundance B‐type and low‐abundance Y‐type inter‐ring fragment ions were indicative of the fatty acyl distribution between the nonreducing and reducing ends of the lipid A backbone. The previously reported lipid A structures of Proteus morganii O34 and Escherichia coli O111 bacteria were used as standards. Although, the fragmentation pathways of the differently phosphorylated lipid A species significantly differed in the negative‐ion mode, they were very similar in the positive‐ion mode. The complementary use of positive‐ion and negative‐ion mode tandem mass spectrometry was found to be essential for the full structural characterization of the C1‐monophosphorylated lipid A species.     

Computational study of SN2 reactions promoted by crown ether: Contact ion pair versus solvent‐separated ion pair mechanism

We examined by quantum chemical methods the mechanism of S_N2 reaction using metal bromide MBr (M = Na, K, Cs) and KX (X= F, Cl) in CH₃CN promoted by crown ether (18‐crown‐6). We focus on whether the metal salts react as a contact ion pair (CIP; M⁺ and X^– in close contact) or as a solvent‐separated ion pair (SSIP; M⁺ and X^– at large distance). In SSIP mechanism, X^– is removed far enough from M⁺ for the metal salt to be considered as “separated” by the effects of the crown ether and the solvent. In the CIP picture, conversely, the coordination of 18‐crown‐6 to M⁺ is not sufficient to overcome the powerful Coulombic interactions between M⁺ and X^–. We find that the CIP route is favored for S_N2 bromination processes using MBr (M = Na, K, Cs). For S_N2 reaction using KF, the feasibility of the two pathways is essentially equal, whereas for S_N2 chlorination by KCl the SSIP route is predicted to be favored.     

Application of pathways activity profiling to urine metabolomics for screening Qi‐tonifying biomarkers and metabolic pathways of honey‐processed Astragalus

Honey‐processed Astragalus, a widely used Qi‐tonifying and immunomodulating herb in traditional Chinese medicine, has strengthened the tonic effects and achieved fewer side effects compared with astragali radix in clinical application. Here, we focus on Qi‐tonifying biomarkers and pathways of honey‐processed Astragalus using urine metabolomics that provide the basis for building the linkage between metabolites in rat urine and its symptoms. The spleen Qi deficiency model group, normal group, astragali radix group, and honey‐processed Astragalus group were implemented to evaluate Qi‐tonifying effects. Twelve potential biomarkers were screened by multivariate statistical analysis by using ultra high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry. Furthermore, pathways activity profiling showed unique pathways that are primarily involved in tryptophan metabolism, tricarboxylic acids cycle, and methionine metabolism. The results demonstrated that metabolomics coupled with pathway activity profiling were promising tools. It might serve as a novel methodological clue to systematically dissect the underlying Qi‐tonifying mechanism of honey‐processed Astragalus.     

Theoretical studies on a possible synthesis reaction pathway on N8 (CS) clusters

The potential energy surfaces of N₈ clusters were investigated by density functional theory (DFT) and a possible synthesis reaction pathway for N₈ (C_S) was suggested. The species involved were fully optimized up to the B3LYP/6‐311+G* level of theory. Relative energies were further calculated at the QCISD/6‐311+G*//B3LYP/6‐311+G* level. The reaction rate constants of these steps from the 1 (N₅⁺?N₃^?, complex, C_S) to 2 (N₈, C_S), 2 (N₈, C_S) to 3 (N₈, C_S), 3 (N₈, C_S) to 4 (N₈, D_2d), and 4 (N₈, D_2d) to 5 (N₈, C_S) reactions were predicted by the VTST theory. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1334–1339, 2001