Rapid modifications of N-substitution in iminosugars: development of new ß-glucocerebrosidase inhibitors and pharmacological chaperones for Gaucher disease.

The rapid discovery of ß-glucocerebrosidase (GCase) inhibitors and pharmacological chaperones for Gaucher disease is described. The N-aminobutyl DNJ-based iminosugar was synthesized and conjugating with a variety of carboxylic acids to generate a N-diversely substituted iminosugar-based library. Several members of this library were found to be nanomolar-range inhibitors of GCase; the inhibition constant Ki of the most potent was found to be 71nM. Although these new molecules showed reasonable chaperoning activity (1.5- to 1.9-fold) in the N370S fibroblast of Gaucher patient-derived cell line, this was accompanies by a concomitant decrease in the cellular α-glucosidase activity, which might limit their further therapeutic potential. Next, newly developed N-substituents were assembled with pyrrolidine-based scaffolds to generate new molecules for further evaluation. The new 2,5-dideoxy-2,5-imino-d-mannitol (DMDP)-based iminosugar 22 was found to exhibit a satisfactory chaperoning activity to enhance GCase activity by 2.2-fold in Gaucher N370S cell line, without impairment of cellular α-glucosidase activity.

Synthesis and Characterization of Curcumin Incorporated Multi Component Nano-Scaffold with Enhanced Anti-bacterial and Wound Healing Properties.

BACKGROUND: Wound healing is one of the major challenges in chronic diseases; the current treatment options are less effective with undesirable side effects and are expensive. Extensive research is carried out to develop cost-effective, natural, biodegradable wound dressings that can reduce oxidative stress and inflammation and prevent bacterial infections. Curcumin has a plethora of therapeutic applications; however, its low solubility limits its clinical use. OBJECTIVE: In this study, curcumin nanoparticles (Cur NP) and curcumin-chitosan nanoparticles (CCNP) were incorporated into the chitosan collagen vanillin scaffold, characterized, and investigated their potential wound healing properties. METHODS: The nano-scaffolds were prepared by freeze-drying method and were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, nanoparticle tracking analysis, and scanning electron microscopy. The drug release, antioxidant, antibacterial, and wound healing properties were assessed by in vitro assays. RESULTS: Cur nano-scaffolds showed particle sizes of 195.9 nm and 110.6 nm for Cur NP+VC and CCNP+VC, respectively. The curcumin encapsulated in the Cur NP+VC and CC+VC nano-scaffolds showed a release profile of > 60% and an improved antioxidant activity of greater than 80%. The nanoscaffolds were antagonistic against Escherichia coli and Staphylococcus aureus and enhanced wound healing capacity of 85.62 % and 77.05% in the murine cell line. CONCLUSION: The curcumin nano-scaffold is a biodegradable and effective drug delivery system for topical use that can act as an antioxidant, facilitate wound healing, as well as prevent bacterial infections.

H101G Mutation in Rat Lens αB-Crystallin Alters Chaperone Activity and Divalent Metal Ion Binding.

BACKGROUND: The molecular chaperone function of αB-crystallins is heavily involved in maintaining lens transparency and the development of cataracts. OBJECTIVES: The aim of the study was to investigate whether divalent metal ion binding improves the stability and αB-crystallin chaperone activity. METHODS: In this study, we have developed an H101G αB-crystallin mutant and compared the surface hydrophobicity, chaperone activity, and secondary and tertiary structure with the wild type in the presence and absence of metal ions. RESULTS: Substitution of His101 with glycine resulted in structural and functional changes. Spectral analysis and chaperone-like activity assays showed that substitution of glycine resulted in a higher percentage of random coils, increased hydrophobicity, and 22±2% higher chaperone-like activity. Whereas in the presence of the Cu2+ ion, H101G exhibited 32±1% less chaperone-like activity compared to the wild type. CONCLUSION: Cu2+ has been reported to enhance the chaperone-like activity of lens α-crystallin. Our results indicate that H101 is the predominant Cu2+ binding site, and the mutation resulted in a partial unfolding that impaired the binding of Cu2+ to H101 residue. In conclusion, this study further helps to understand the important binding site for Cu2+ to αB-crystallin.

Ditopic complexation of selenite anions or calcium cations by pirenoxine: an implication for anti-cataractogenesis.

This study investigated whether and how pirenoxine (PRX) interacts with selenite or calcium ions, as these two ions have been proven respectively a factor leading to the formation of lens cataract. UV, NMR, and isothermal titration calorimetry (ITC) analysis indicated that PRX could bind maximum up to six selenite anions and the binding site preference was concentration dependent with the peripheral binding first followed by the π-π interactions with the aromatic moiety; while for calcium cation interaction the 3-carboxylate and ß-ketoimine functional groups were responsible for chelating calcium ions. The results obtained by MP2/6-31+G(d) molecular orbital calculations provided theoretical evidence in support of the π-π interactions between selenite and the PRX aromatic framework, and further analysis of the binding energies with the aromatic moiety indicates that these interactions take place most likely at the benzoquinone (ring I) π-system. The calcium binding preferences with PRX were also determined based on the stabilization energy obtained by B3LYP/6-31+G(d) calculations, showing the binding preferences were site 2 > site 1 > site 3 > ring II, consistent with the experimental data. The in vitro study of the reduction of selenite or calcium ions-induced lens turbidity by PRX with ditopic recognition properties was thus demonstrated. These results may provide a rationale for using PRX as an anti-cataract agent and warrant further biological studies.

Synergistic Antioxidant and Antibacterial Activity of Curcumin-C3 Encapsulated Chitosan Nanoparticles.

BACKGROUND: Recent studies have focused on the nanoformulations of curcumin to enhance its solubility and bioavailability. The medicinal properties of curcumin-C3 complex, which is a combination of three curcuminoids (curcumin, demethoxycurcumin and bisdemethoxycurcumin) is less explored. OBJECTIVE: The aim of this study was to prepare curcumin-C3 encapsulated in chitosan nanoparticles, characterize and evaluate their antioxidant and antibacterial potential. METHODS: Ionic gelation method was used to prepare curcumin-C3 nanoparticles and was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy and nanoparticle tracking analysis. In vitro assays were performed to assess drug release, antioxidant and antibacterial activities. RESULTS: Curcumin-C3-chitosan nanoparticle showed an increased entrapment efficiency of >90%, drug release and improved antioxidant potential. Moreover, curcumin-C3-chitosan nanoparticle showed stronger inhibition of Escherichia coli and Staphylococcus aureus. CONCLUSION: Chitosan is a suitable carrier for curcumin-C3 nanoparticle and can be used as a drug delivery system in the treatment of inflammatory and bacterial diseases.

Curcumin-C3 Complexed with α-, ß-cyclodextrin Exhibits Antibacterial and Antioxidant Properties Suitable for Cancer Treatments.

BACKGROUND: The curcumin-C3 (cur-C3) complex obtained from Curcuma longa rhizome is a combination of three curcuminoids, namely, curcumin, dimethoxycurcumin, and bisdemethoxycurcumin. Cur and curcuminoids have been extensively researched for their wide range of therapeutic properties against inflammatory diseases, diabetes, and cancer. OBJECTIVE: In spite of their extensive medicinal properties, cur and curcuminoids have poor solubility and bioavailability due to their hydrophobicity. This limitation can be overcome by complexing cur-C3 with natural cyclic oligosaccharides, such as Cyclodextrin (CD). METHODS: In this study, cur-C3 and CD (α, ß) inclusion complexes (ICs) were prepared with different molar ratios and characterized by nuclear magnetic resonance, Fourier transform infrared spectroscopy, X-ray diffraction, and transmission electron microscopy. RESULTS: The cur-C3 cyclodextrin ICs showed an increased entrapment efficiency of 97.8% and improved antioxidant activity compared to cur and can be used as an antioxidant to reduce cancer-related oxidative stress. Additionally, α- CD ICs of curcumin-C3 caused an increase in growth inhibition of Staphylococcus aureus. CONCLUSION: Our findings suggest that both α- and ß-CDs are suitable carriers for cur-C3 and can be used as an effective treatment for cancer-associated oxidative stress and as a preventive treatment for nosocomial infections and pneumonia.

Strategy for determination of in vitro protein acetylation sites by using isotope-labeled acetyl coenzyme A and liquid chromatography-mass spectrometry.

Acetylation of proteins on specific lysine residues by acetyltransferase enzymes is a post-translational modification for biologically relevant regulation. In this study, we proposed a strategy to determine the in vitro acetylation sites of proteins by tracing isotope-labeled acetyl groups using mass spectrometry. Isotope-labeled and unlabeled acetyl groups transferred onto the substrates in vitro result in a specific "mass difference" that can be measured by MS analysis and utilized for localization of potential acetylated peptide signals. The identification of acetylation site is facilitated by conducting MS/MS experiments on those selected signals. Acetylation reactions of substrates were performed in the presence of acetyltransferase and equal molar of isotope-labeled acetyl coenzyme A ([(13)C2-2-D3]-acetyl-CoA) and unlabeled acetyl-CoA. After enzymatic digestion, the resulting peptide mixture was fractionated by off-line, reversed-phase high-pressure liquid chromatography and the accurate mass measurement of peptides was achieved by a quadrupole/time-of-flight mass spectrometer. Signals with 5-Da (or their multiples) mass differences and equal responses were selected out by program computation. Those potential acetylated peptide signals were subjected to MS/MS analyses for determination of acetylation sites. We have used histone H3 peptide (aa 1-20), histone H2B peptide (aa 1-21), histone H2A, and histone H2B proteins as the model compounds to demonstrate the applicability of this analytical scheme for the characterization of in vitro acetylation sites.

Astaxanthin protects against oxidative stress and calcium-induced porcine lens protein degradation.

Astaxanthin (ASTX), a carotenoid with potent antioxidant properties, exists naturally in various plants, algae, and seafoods. In this study, we investigated the in vitro ability of ASTX to protect porcine lens crystallins from oxidative damage by iron-mediated hydroxyl radicals or by calcium ion-activated protease (calpain), in addition to the possible underlying biochemical mechanisms. ASTX (1 mM) was capable of protecting lens crystallins from being oxidized, as measured by changes in tryptophan fluorescence, in the presence of a Fenton reaction solution containing 0.2 mM Fe2+ and 2 mM H2O2. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis demonstrated that beta(high)-crystallin was the most vulnerable protein under these conditions of free radical exposure. The proteolysis of lens crystallins induced by calcium ion-activated calpain was also inhibited by ASTX (0.03-1 mM) as determined by daily measurement of the light-scattering intensity at 405 nm for five consecutive days. ASTX at 1 mM was as potent as a concentration of 0.1 mM calpain inhibitor E64 in protecting the oxidative damage/hydrolysis of porcine crystallins. At a concentration of 1 mM, ASTX provided better protection than the endogenous antioxidant glutathione in terms of suppressing calcium-induced turbidity of lens proteins. Thin-layer chromatography analysis indicated that ASTX interacted with calcium ions to form complexes, which we believe interfere with the hydrolysis of lens crystallins by calcium-activated calpain. This in vitro study shows that ASTX is capable of protecting porcine lens proteins from oxidative insults and degradation by calcium-induced calpain.

Anticataractogenesis Mechanisms of Curcumin and a Comparison of Its Degradation Products: An in Vitro Study.

Curcumin (Cur) exhibits anticataractogenesis activity. This study aimed to compare the activities of Cur with those of its degradation products in a series of in vitro lens protein turbidity assays. The results show that Cur (200 µM) ameliorates selenite-induced crystallin aggregation, and the mean OD value was 0.10 ± 0.02 (p < 0.05), which was significantly different from controls (0.15 ± 0.01) after incubating for 3 days. However, Cur did not significantly inhibit calcium-induced proteolysis after incubating for 3 days. Such results were supported by isothermal titration calorimetry observation that Cur binds with selenite but not with calcium. Presence of Cur and the degradation products examined (ferulic acid, cinnamic acid, vanillin, and vanillic acid) indicates significantly protective activities on lens γ-crystallins after UVC exposure for 3 h. Among the compounds examined, only ferulic acid exhibited a significant inhibitory effect against UVB-induced turbidity with a mean OD of 0.32 ± 0.01 (p < 0.05), which was significantly different from controls (0.49 ± 0.02). The previously reported anticataract effects of Cur may stem not only from Cur but also from its degradation products through various cataractogenesis mechanisms in vitro.

The Comparative Studies of Binding Activity of Curcumin and Didemethylated Curcumin with Selenite: Hydrogen Bonding vs Acid-Base Interactions.

In this report, the in vitro relative capabilities of curcumin (CCM) and didemethylated curcumin (DCCM) in preventing the selenite-induced crystallin aggregation were investigated by turbidity tests and isothermal titration calorimetry (ITC). DCCM showed better activity than CCM. The conformers of CCM/SeO3(2-) and DCCM/SeO3(2-) complexes were optimized by molecular orbital calculations. Results reveal that the selenite anion surrounded by CCM through the H-bonding between CCM and selenite, which is also observed via IR and NMR studied. For DCCM, the primary driving force is the formation of an acid-base adduct with selenite showing that the phenolic OH group of DCCM was responsible for forming major conformer of DCCM. The formation mechanisms of selenite complexes with CCM or DCCM explain why DCCM has greater activity than CCM in extenuating the toxicity of selenite as to prevent selenite-induced lens protein aggregation.

Hospitalized pediatric parainfluenza virus infections in a medical center.

BACKGROUND/PURPOSE: Parainfluenza viruses (PIVs) are common pathogens in respiratory tract infections. The aims of this study were to determine the clinical presentation of PIV infections in hospitalized children and to identify particular clinical indications that may effectively distinguish between different PIV serotypes. METHODS: A retrospective review of data from children hospitalized with PIV infections at the Mackay Memory Hospital in Taipei between January 2005 and December 2007 was undertaken. Symptoms, signs, laboratory findings and seasonal variations between different types of PIV (serotypes 1, 2 and 3) were compared. RESULTS: A total of 206 patients [119 (57.8%) boys and 87 (42.2%) girls] were enrolled in the study. Seventy-four (35.9%) patients were infected with PIV serotype 1, 25 (12.1%) with serotype 2 and 107 (51.9%) with serotype 3. The most common clinical presentations were fever (81.1%), cough (66.0%), rhinorrhea (44.2%) and hoarseness (22.3%); 4.9% of the infected children also had skin rashes. No significant differences were found in average white blood cell counts and C-reactive protein levels between the three serotypes. PIV serotype 1 infections were discernible throughout the year; serotype 2 tended to cluster in the late summer and autumn of 2005 and 2007; and serotype 3 was more common in the spring and early summer. CONCLUSION: The clinical presentation of PIV infection in hospitalized children ranges from upper respiratory tract infection to croup, bronchiolitis and viral bronchopneumonia, with the different types of PIV infections giving rise to similar symptoms. The seasonal distribution of the different serotypes is, nevertheless, quite distinct.