Putative biomarker for phospholipid accumulation in cultured cells treated with phospholipidosis-inducing drugs: alteration of the phosphatidylinositol composition detected using high-performance liquid chromatography-tandem mass spectrometry.

We developed a high-performance liquid chromatography-tandem mass spectrometric method for phospholipid biomarker discovery and applied it to a cell-based assay system for the screening of phospholipidosis-inducing drugs. We studied the compositions of phospholipid molecules exceeding 100 species in cultured cells and found a characteristic alteration in the composition by treatment with cationic amphiphilic drugs possessing phospholipidosis-inducing potency. The compositions of phosphatidylinositol in RAW264 cells were significantly affected by the drug treatment. Similar alterations were also found in THP-1 cells. These phenomena were not observed when cells were treated with warfarin, which does not have phospholipidosis-inducing potency. Structural analysis of the altered phosphatidylinositols by a product ion scan revealed the presence of certain fatty acyl chains. Based on our findings, we proposed a prediction parameter (PP) for phospholipid accumulation calculated from the relative compositions of phosphatidylinositol species. As the dosage of imipramine (a cationic amphiphilic drug) increased, both the PP and cellular phospholipid content increased. Our results suggest that PP has potency as a biomarker for phospholipid accumulation in cells treated with drugs.

Maintenance of luminal pH and protease activity in lysosomes/late endosomes by vacuolar ATPase in chlorpromazine-treated RAW264 cells accumulating phospholipids.

Cationic amphiphilic drugs (CADs) inhibit phospholipases competitively/uncompetitively. It has also been reported that CADs spontaneously accumulate in acidic organelles and increase their luminal pH, which may lead to deactivation of phospholipid-metabolising enzymes, causing cellular phospholipid accumulation. Recently, however, contradictory results have also been reported in that the luminal pH is not increased by CAD treatment. In this study, we examined whether the lysosomal/late endosomal acidic pH was maintained by vacuolar ATPase (v-ATPase) after treatment with chlorpromazine (CPZ) as a model CAD. The activity of lysosomal protease after CPZ treatment was also measured. Oregon Green-dextran-tetramethylrhodamine conjugate was employed to determine the luminal pH of the lysosomes/late endosomes in RAW264 cells. The luminal pH remained acidic after treatment with CPZ for 23 h, and the lysosomal protease activity was not decreased by 5-min CPZ treatment. Co-treatment with CPZ and bafilomycin A1 (v-ATPase inhibitor) raised the luminal pH. These results suggest that the lysosomal/late endosomal pH is not affected by a 23-h CPZ treatment. In addition, lysosomal enzymes presumably maintain their activity when CPZ accumulates. Our results imply that the pH homeostasis in lysosomes/late endosomes is strictly maintained even after a longer treatment with CADs.

Preparation of branched cyclomaltoheptaose with 3-O-α-L-fucopyranosyl-α-D-mannopyranose and changes in fucosylation of HCT116 cells treated with the fucose-modified cyclomaltoheptaose.

From a mixture of 4-nitrophenyl α-L-fucopyranoside and D-mannopyranose, 3-O-α-L-fucopyranosyl-D-mannopyranose was synthesised through the transferring action of α-fucosidase (Sumizyme PHY). 6(I),6(IV)-Di-O-(3-O-α-L-fucopyranosyl-α-D-mannopyranosyl)-cyclomaltoheptaose {8, 6(I),6(IV)-di-O-[α-L-Fuc-(1→3)-α-D-Man]-ßCD} was chemically synthesised using the trichloroacetimidate method. The structures were confirmed by MS and NMR spectroscopy. A cell-based assay using the fucosyl ßCD derivatives, including the newly synthesised 8, showed that derivatives with two branches of the α-L-Fuc or α-L-Fuc-(1→3)-α-D-Man residues possessed slight growth-promoting effects and lower toxicity in HCT116 cells compared to those with one branch. These compounds may be useful as drug carriers in targeted drug delivery systems.

Improved capillary electrophoresis method for the analysis of carbohydrate-deficient transferrin in human serum, avoiding interference by complement C3.

Capillary electrophoresis (CE) methods for transferrin analysis are widely used in clinical laboratories, but complement C3 peaks often overlap with carbohydrate-deficient transferrin peaks. In this study, we discovered that the electrophoretic mobility of the complement C3 peak could be controlled by adding carboxymethylcellulose (CMC) and dextran sulfate (DS) to the background electrolyte solution, probably because of adsorption of the polyanions to the proteins. The improved capillary electrophoresis method was developed using spermine, CMC, and DS as the background electrolyte solution additives. The carbohydrate-deficient transferrin concentrations determined using this system were in good agreement with those determined by HPLC, with acceptable reproducibility. These results suggest that this method has the potential to be developed into a new clinical test.

Role of bis(monoacylglycero)phosphate in propranolol binding to phospholipid membranes under acidic conditions as measured by high-performance frontal analysis/capillary electrophoresis.

Bis(monoacylglycero)phosphate (BMP) is localized in acidic organelles such as late endosomes or lysosomes. It has been reported that BMP levels increase under phospholipidosis induced by cationic amphiphilic drugs. In the present study, the effect of BMP on the binding of propranolol (PRO) to phospholipid liposomes under acidic conditions was investigated. Binding experiments were conducted by high-performance frontal analysis/capillary electrophoresis. PRO showed nonspecific binding to BMP-containing liposomes (BMP:phosphatidylcholine = 1:4), when numbers of bound drug molecules per lipid molecule (r) ranged 0.01-0.06. Total binding affinity increased depending on the BMP content. Binding affinity was decreased by low ionic strength, or by substitution of BMP with diacylglycerol, suggesting that electrostatic interactions were involved. The binding-enhancement effect of BMP was almost equivalent to that of phosphatidylglycerol, and slightly larger than that of phosphatidylserine. An acidic environment (pH 5.0) decreased total binding affinity to BMP-containing liposomes. This could be explained by the pH-partition theory (i.e., the loss in affinity was caused by a decrease in the neutral form of the drug accessible to the membrane core). These results suggest that PRO binding is enhanced by BMP in late endosomes or lysosomes, whereas an acidic environment weakens such binding.

Preparation, characterization, and biological evaluation of 6(I),6(IV)-di-O-[α-l-fucopyranosyl-(1→6)-2-acetamido-2-deoxy-ß-d-glucopyranosyl]-cyclomaltoheptaose and 6-O-[α-l-fucopyranosyl-(1→6)-2-acetamido-2-deoxy-ß-d-glucopyranosyl]-cyclomaltoheptaose.

6(I),6(IV)-Di-O-[α-l-fucopyranosyl-(1→6)-2-acetamido-2-deoxy-ß-d-glucopyranosyl]-cyclomaltoheptaose (ßCD) {6(I),6(IV)-di-O-[α-l-Fuc-(1→6)-ß-d-GlcNAc]-ßCD (5)} and 6-O-[α-l-fucopyranosyl-(1→6)-2-acetamido-2-deoxy-ß-d-glucopyranosyl]-ßCD {6-O-[α-l-Fuc-(1→6)-ß-d-GlcNAc]-ßCD (6)} were chemically synthesized using the corresponding authentic compounds, bis(2,3-di-O-acetyl)-pentakis(2,3,6-tri-O-acetyl)-ßCD as the glycosyl acceptor and 2,3,4-tri-O-benzyl-α-l-fucopyranosyl-(1→6)-3,4-di-O-acetyl-2-deoxy-2-(2,2,2-trichloroethoxycarbonylamino)-d-glucopyranosyl trichloroacetimidate as the fuco-glucosaminyl donor. NMR confirmed that α-l-Fuc-(1→6)-d-GlcNAc was bonded by ß-linking to the ßCD ring. To evaluate biological efficiency, the biological activities of the new branched ßCDs were examined. The cell detachment activity of 5 was lower than that of 6 in real-time cell sensing (RT-CES) assay, indicating that 5 has lower toxicity. In SPR analysis, 5 had a higher special binding with AAL, a fucose-recognizing lectin. These results suggest that 5 could be an efficient drug carrier directed at cells expressing fucose-binding proteins.

Preparation and characterization of branched beta-cyclodextrins having alpha-L-fucopyranose and a study of their functions.

Three positional isomers of 6(1),6(n)-di-O-(alpha-L-fucopyranosyl)-beta-cyclodextrin [6(1),6(n)-di-O-(alpha-L-Fuc)-betaCD, n=2-4] were chemically synthesized by using the corresponding authentic compounds, 6(1),6(n)-di-O-(tert-butyldimethylsilyl)-betaCD (n=2-4) as fucosyl acceptors and 2,3,4-tri-O-benzyl-L-fucopyranosyl trichloroacetimidate as a fucosyl donor. Their structures were analyzed by HPLC, MS and NMR spectroscopy. The hemolytic activities of the alpha-L-Fuc-betaCDs were lower than that of betaCD, while the water solubility of these branched betaCDs was much higher than that of betaCD. The molecular interaction between these compounds and the fucose-binding lectin, Aleuria aurantia lectin (AAL), was investigated by using an optical biosensor based on the surface plasmon resonance (SPR) technique. The order of binding affinity, as a function of the fucose-binding position, was 6(1),6(4)- > 6(1),6(3)- > 6(1),6(2)-di-O-(alpha-L-Fuc)-betaCD > 6-O-(alpha-L-Fuc)-betaCD.

Determination of branched beta-cyclodextrin-prostaglandin complexes using electrospray ionization mass spectrometry.

Mass spectral measurements by electrospray ionization mass spectrometry (ESI-MS) detected the ions of beta-cyclodextrin (betaCD) or branched betaCDs (glucosyl-, galactosyl-, mannosyl- and maltosyl-betaCD)-prostaglandins (PGs: PGA(2), PGD(2), PGE(1), PGE(2), PGF(2alpha) and PGJ(2)) complexes, i.e., betaCD-PG complexes, with a host:guest ratio of 1:1 in the negative ion mode. This is the first study to report the ions of branched betaCD-PG complexes using ESI-MS. The inclusion complexes were determined by a flow injection analysis using acetonitrile/water. We could confirm by this method the presence of a betaCD-PGE(2) complex with a host:guest ratio of 1:1 in a solution-dissolved pharmaceutical formulation consisting of betaCD-PGE(2) (Prostarmon E tablet).

Microdose clinical trial: quantitative determination of fexofenadine in human plasma using liquid chromatography/electrospray ionization tandem mass spectrometry.

A sample treatment procedure and high-sensitive liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method for quantitative determination of fexofenadine in human plasma was developed for a microdose clinical trial with a cold drug, i.e., a non-radioisotope-labeled drug. Fexofenadine and terfenadine, as internal standard, were extracted from plasma samples using a 96-well solid-phase extraction plate (Oasis HLB). Quantitation was performed on an ACQUITY UPLC system and an API 5000 mass spectrometer by multiple reaction monitoring. Chromatographic separation was achieved on an XBridge C18 column (100 mm x 2.1 mm i.d., particle size 3.5 microm) using acetonitrile/2 mM ammonium acetate (91:9, v/v) as the mobile phase at a flow rate of 0.6 ml/min. The analytical method was validated in accordance with the FDA guideline for validation of bioanalytical methods. The calibration curve was linear in the range of 10-1000 pg/ml using 200 microl of plasma. Analytical method validation for the clinical dose, for which the calibration curve was linear in the range of 1-500 ng/ml using 20 microl of plasma, was also conducted. Each method was successfully applied for making determinations in plasma using LC/ESI-MS/MS after administration of a microdose (100 microg solution) and a clinical dose (60 mg dose) in eight healthy volunteers.

Preparation and characterization of 6I,6n-di-O-(L-fucopyranosyl)-beta-cyclodextrin (n=II-IV) and investigation of their functions.

Three positional isomers of 6(I),6(n)-di-O-(beta-L-fucopyranosyl)-cyclomaltoheptaose [6(I),6(n)-di-O-(beta-L-Fuc)-beta-cyclodextrin, -betaCD, n=II-IV] were chemically synthesized using the corresponding authentic compounds, 6(I),6(n)-di-O-(tert-butyldimethylsilyl)-betaCD (n=II-IV), as the fucosyl acceptors, and 2,3,4-tri-O-acetyl-L-fucopyranosyl trichloroacetimidate as the fucosyl donor. Their structures were analyzed by HPLC, MS, and NMR spectroscopy. The hemolytic activities of L-Fuc-betaCDs were lower than that of betaCD, while the solubilities of these branched CDs in water were much higher than that of betaCD. The molecular interaction between these compounds and the fucose-binding lectin Aleuria aurantia lectin (AAL) was investigated using an optical biosensor based on a surface plasmon resonance (SPR) technique. The order of binding affinity, as a function of the fucose-binding position, was 6(I),6(IV)->6(I),6(III)->6(I),6(II)-di-O-(beta-L-Fuc)-betaCD>6-O-(beta-L-Fuc)-betaCD.

Synthesis of novel heterobranched beta-cyclodextrins having beta-D-N-acetylglucosaminyl-maltotriose on the side chain.

From a mixture of N-acetylglucosaminyl-beta-cyclodextrin (GlcNAc-betaCD) and lactose, beta-D-galactosyl-GlcNAc-betaCD (Gal-GlcNAc-betaCD) was synthesized by the transfer action of beta-galactosidase. GlcNAc-maltotriose (Glc3) and Gal-GlcNAc-Glc3 were produced with hydrolysis of GlcNAc-betaCD by cyclodextrin glycosyltransferase, and Gal-GlcNAc-betaCD by bacterial saccharifying alpha-amylase respectively. Finally, GlcNAc-Glc3-betaCD and Gal-GlcNAc-Glc3-betaCD were synthesized in 5.2% and 3.5% yield when Klebsiella pneumoniae pullulanase was incubated with the mixture of GlcNAc-Glc(3) and betaCD, or Gal-GlcNAc-Glc3 and betaCD respectively. The structures of GlcNAc-Glc3-betaCD and Gal-GlcNAc-Glc3-betaCD were analyzed by FAB-MS and NMR spectroscopy and identified as 6-O-alpha-(6(3)-O-beta-D-N-acetylglucosaminyl-maltotriosyl)-betaCD, and 6-O-alpha-(4-O-beta-D-galactopyranosyl-6(3)-O-beta-D-N-acetylglucosaminyl-maltotriosyl)-betaCD respectively.

Screening of bitterness-suppressing agents for quinine: the use of molecularly imprinted polymers.

The purpose of the present study was to examine the possibility of using molecularly imprinted polymers (MIPs) to screen for bitterness-suppressing agents. Quinine was selected as the bitter substance standard. L-arginine (L-Arg), L-ornithine (L-Orn), L-lysine (L-Lys), and L-citrulline (L-Ctr) were tested as bitterness suppressant candidates. In a high-performance liquid chromatography study using a uniformly sized MIP for cinchonidine, which has a very similar structure to quinine, the retention factor (k) of quinine was significantly shortened by the addition of L-Arg or L-Orn to the mobile phase, whereas slight or no decrease was observed when L-Ctr and L-Lys were added. The abilities of these amino acids to decrease the k of quinine were ranked in the following order: L-Arg = (L-Orn >(L-Ctr >>(L-Lys. A linear relationship between the reciprocal of k and the concentration of the amino acids indicated a single competitive model at a single site. The magnitude of the association constants obtained seemed to be directly related to the inhibitory effect of the test substances on the affinity of quinine for the receptor site. Nuclear magnetic resonance and molecular modeling studies suggested a one-to-two hydrogen-bonding-based complex formation of one quinine molecule with two methacrylic acid molecules (Q-2MAA) in chloroform. In the molecular modeling studies, the N--N distance of the quinine molecule in the assumed Q-2MAA complex was calculated to be 5.12 angstroms, similar to the N - N distances of the two amino acid complexes (L-Arg-2MAA, L-Orn-2MAA), which were 4.84 and 5.30 angstroms, respectively. This suggests that L-Arg and L-Orn may compete with the quinine molecule in the cinchonidine-imprinted space. Finally, the results of human gustatory sensation tests correlated well with the MIP data. The proposed method using MIPs seems to have a potential for screening bitterness-suppressing agents for quinine.

Preparation and characterization of novel branched beta-cyclodextrins having beta-D-galactose residues on the non-reducing terminal of the side chains and their specific interactions with peanut (Arachis hypogaea) agglutinin.

Six novel branched beta-cyclodextrins (betaCDs) having beta-D-galactose residues on the non-reducing terminal of the sugar side chains, namely 6(1),6(4)-di-O-(beta-D-galactosyl)-betaCD (10), 6-O-(beta-D-galactosyl)-betaCD (11), 6(1),6(4)-di-O-(beta-lactosyl)-betaCD (14), 6-O-(beta-lactosyl)-betaCD (15), 6(1),6(4)-di-O-(4'-O-beta-D-galactosyl-beta-lactosyl)-betaCD (18), and 6-O-(4'-O-beta-D-galactosyl-beta-lactosyl)-betaCD (19), were chemically synthesized using the trichloroacetimidate method. The reaction products were separated by HPLC on an amino column into dibranched and monobranched betaCDs. Their structures were confirmed by mass spectrometry (MS) and two-dimensional (2D) NMR spectroscopic analysis. To study the length of the sugar side chains attached to the CD ring, which leads to differences in the functions of the branched CDs, interactions of these compounds with peanut (Arachis hypogaea) agglutinin (PNA) were investigated using an optical biosensor and an inhibition assay based on hemagglutination. The results showed that all branched betaCDs interacted with PNA, and the binding affinity was 18>14>10 and 19>15>11 when the derivatives were compared on the basis of side chain length.

Preparation and reactivity of a novel disaccharide, glucosyl 1,5-anhydro-D-fructose (1,5-anhydro-3-O-alpha-glucopyranosyl-D-fructose).

A novel disaccharide, glucosyl 1,5-anhydro-D-fructose (1,5-anhydro-3-O-alpha-glucopyranosyl-D-fructose, GAF) was enzymatically prepared from 1,5-anhydro-D-fructose (1,5-AF) and cyclomaltoheptaose (beta-cyclodextrin). Cyclodextrin glucanotransferase transferred various sizes of maltooligosaccharide to 1,5-AF. Glucoamylase digested the maltooligosyl chain of the products to a glucosyl residue giving a final product, GAF. An NMR analysis of GAF elucidated that the glucose residue was linked to C-3 of the 1,5-AF residue with an ether linkage. Reactivity on the aminocarbonyl reaction of GAF with bovine serum albumin was lower than that of 1,5-AF, but was higher than that of glucose.

HPLC analysis of manno-oligosaccharides derived from Saccharomyces cerevisiae mannan using an amino column or a graphitized carbon column.

The chromatographic behavior of manno-oligosaccharides derived from Saccharomyces cerevisiae mannan on two kinds of HPLC columns, an aminopropyl-silica column or a graphitized carbon column (GCC), was investigated. The order of elution of manno-oligosaccharides on both columns with acetonitrile-water was almost the same, that is, the retention increased with increasing molecular size. However, the GCC made it possible to isolate completely two isomers of mannotrioses (M(3)-1 and M(3)-2) with different linkage positions. We reinvestigated the structures of mannobiose (M(2)), M(3)s, and mannotetraose (M(4)) that were completely isolated by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and NMR spectroscopy.

Enzymatic Synthesis of Mannosyl-cyclodextrin by α-Mannosidase from Jack Bean.

Mannosylated derivatives of cyclodextrins (CDs), mannosyl-α, ß, and γCD were synthesized from a mixture of mannose and α, ß, and γCD by the reverse action of α-mannosidase from jack bean, respectively. Their structures were analyzed by FAB-MS and 13C-NMR spectroscopies, and they were identified as 6-O-α-d-mannosyl-α, ß, and γCD. The optimum conditions for the production of 6-O-α-d-mannosyl-αCD by α-mannosidase were examined. Optimum pH and temperature were pH 4.5 and 60°C, respectively. Yield of mannosyl-αCD increased with increasing mannose concentration and reached more than 35% (mol/mol) at the concentration of 2 m mannose and 0.4 m αCD.