Biomedical subjects

Ying Wang

Publications and source records attributed to Ying Wang.

At least 253 records · Page 14Linked to original sources

PubMed2005

[The role of CXCR4 in lung cancer metastasis and its possible mechanism].

OBJECTIVE: To investigate the role of CXCR4 in the metastasis of human lung cancer and its possible mechanism. METHODS: Lung cancer cells of the lines 95C and 95D with high or low metastatic potential were transfeted with CXCR4 antisense plasmid pcDNA-ASX4, whole length eukaryotic expression plasmid pcDNA-CXCR4 (95D-ASX4 and 95C-X4 cell lines), and corresponding plasmid pcDNA3 (95C-pC and 95D-pC cell lines). 95C, 95C-pC, 95C-X4, 95D, and 95D-pC cells were injected subcutaneously into Balb/c nu/nu mice, 4 approximately 5 mice in a group. The mice were observed twice a week. Ten weeks later the mice were killed and the tumor in situ and the lungs were taken out to undergo histological examination. The effect of CXCR4 expression on the cell migration, MMP-2 activity, adhesion and GRO-a expression of lung cancer cells were detected by chemotaxis and chemoinvasion assay, zymography, adhesion assay and RT-PCR respectively. The polymerization of F-actin was measured by FACS and confocal microcopy. Western blotting was used to detect the phospharylation of ERK1/2 in 85D cells RESULTS: Metastasis was not found in the mice injected with 95C and 95C-pC cells, and was seen in 2/5 of the mice injected with 95C-X4 cells, 3/4 of the mice injected with 95D and 95D-pC cells, 2/5 of the mice injected with 95D-ASX4 cells, however, the number of metastatic nodes in the lungs of 95D-ASX4 group was significantly less than those in the 95D and 95D-pC groups (P = 0.044). SDF-1a, a CXCR4 specific ligand, induced the migratory response and F-actin polymerization in the lung cancer cells; SDF-1a promoted the MMP-2 activity, the adhesion to vascular endothelial cells and GRO-a expression; and neutralizing CXCR4 antibody inhibited these effects to some degree. Moreover, SDF-1a induced the phosphorylation of ERK1/2 in human lung cancer cells. CONCLUSION: Metastasis of human lung cancer depends on, to some degree, the interaction of CXCR4 and SDF-1 that are involved in this process by regulating the active locomotion, MMP-2 activity, adhesion ability or GRO-a expression.

Animals↗

PubMed2005

RIN1 is an ABL tyrosine kinase activator and a regulator of epithelial-cell adhesion and migration.

BACKGROUND: ABL tyrosine kinases control actin remodeling in development and in response to environmental stimuli. These changes affect cell adhesion, cell migration, and cell-cell contact. Little is known, however, about upstream mechanisms regulating ABL protein activation. RESULTS: We report that the RAS effector RIN1 is an activator of ABL tyrosine kinases. RIN1 expression in fibroblasts promotes the formation of membrane spikes; similar effects have been reported for ABL overexpression. RIN1 binds to the ABL SH3 and SH2 domains, and these interactions stimulate ABL2 catalytic activity. This leads to increased phosphorylation of CRK and CRKL, inhibiting these cytoskeletal regulators by promoting intramolecular over intermolecular associations. Activated RAS participates in a stable RAS-RIN1-ABL2 complex and stimulates the tyrosine kinase-activation function of RIN1. Deletion of the RAS binding domain (RBD) strongly stimulated the ABL2 activation function of RIN1, suggesting that RAS activation results from the relief of RIN1 autoinhibition. The ABL binding domain of RIN1 (RIN1-ABD) increased the activity of ABL2 immune complexes and purified RIN1-ABD-stimulated ABL2 kinase activity toward CRK. Mammary epithelial cells (MECs) from Rin1-/- mice showed accelerated cell adhesion and increased motility in comparison to wild-type cells. Knockdown of RIN1 in epithelial-cell lines blocked the induction of CRKL phosphorylation, confirming that RIN1 normally functions as an inhibitor of cell motility. CONCLUSIONS: RIN1 is a directly binding ABL tyrosine kinase activator in cells as well as in a defined-component assay. In response to environmental changes, this novel signal pathway mediates actin remodeling associated with adhesion and migration of epithelial cells.

Actins↗

PubMed2005

Probing the role of negatively charged amino acid residues in ion permeation of skeletal muscle ryanodine receptor.

Sequence comparison suggests that the ryanodine receptors (RyRs) have pore architecture similar to that of the bacterial K+ channel KcsA. The lumenal loop linking the two most C-terminal transmembrane spanning segments in the RyRs has a predicted pore helix and an amino acid motif (GGGIG) similar to the selectivity filter (TVGYG) of KcsA identified by x-ray analysis. The RyRs have many negatively charged amino acid residues in the two regions linking the GGGIG motif and predicted pore helix with the two most C-terminal transmembrane spanning segments. We tested the role of these residues by generating single-site mutants, focusing on amino acid residues conserved among the mammalian RyRs. Replacement of two acidic residues immediately after the GGGIG motif in skeletal muscle ryanodine receptor (RyR1-D4899 and -E4900) with asparagine and glutamine profoundly affected ion permeation and selectivity. By comparison, mutagenesis of aspartate and glutamate residues in the putative linker regions showed a K+ conductance and selectivity for Ca2+ compared to K+ (P(Ca)/P(K)) close to wild-type. The results show that the negatively charged carboxyl oxygens of D4899 and E4900 side chains are major determinants of RyR ion conductance and selectivity.

Amino Acid Motifs↗

PubMed2005

A unique highly oxygenated pyrano[4,3-c][2]benzopyran-1,6-dione derivative with antioxidant and cytotoxic activities from the fungus Phellinus igniarius.

[structure: see text] A unique pyrano[4,3-c][2]benzopyran-1,6-dione derivative with an unprecedented carbon skeleton, phelligridin G (1), has been isolated from the fruiting body of the fungus Phellinus igniarius. Its structure was elucidated by detailed spectroscopic analysis. A possible biogenetic origin of 1 mediated by the fungal metabolite precursor 4-hydroxy-6-methyl-2-pyrone was postulated. Phelligridin G (1) showed antioxidant activity inhibiting rat liver microsomal lipid peroxidation and moderate selective cytotoxic activities against human cancer cell lines.

Animals↗

PubMed2005

Mutation analysis of the flp operon in Actinobacillus actinomycetemcomitans.

Fresh clinical isolates of the periodontal pathogen Actinobacillus actinomycetemcomitans live as autoaggregates, in which cells are densely packed and embedded in an extracellular matrix composed of bundled fimbriae, exopolymers, and vesicles. The expression of fimbriae is known to be determined by the flp operon of 14 genes, flp-1-flp-2-tadV-rcpCAB-tadZABCDEFG. We generated mutations of each gene of this operon in A. actinomycetemcomitans strain D7S. All mutants expressed some changes in the production of extracellular matrix materials that include vesicles, exopolymers, and fimbriae. The expression of fimbriae required the function of flp-1, rcpA, rcpB, tadB, tadD, tadE, and tadF. Mutants of flp-2, tadZ, tadA, tadC, and tadG expressed reduced levels of fimbriae, or fimbriae that had different gross appearance. Importantly, the expression of the non-fimbrial matrix materials was affected by all mutations, suggesting that the flp operon was involved in production of these materials. The flp locus apparently plays a central role in autoaggregation of A. actinomycetemcomitans, which may be the primary survival strategy of this bacterium in vivo.

Aggregatibacter actinomycetemcomitans↗

PubMed2005

Endoplasmic reticulum targeting sequence enhances HBV-specific cytotoxic T lymphocytes induced by a CTL epitope-based DNA vaccine.

CD8(+) T cells play a critical role in protective immunity against Hepatitis B Virus (HBV). Epitope-based DNA vaccines expressing HBV-dominant CTL epitopes can be used as candidate vaccines capable of inducing cytotoxic T Lymphocytes (CTL) responses. A plasmid DNA encoding a CTL epitope of HBV core antigen, HBc(18-27), was constructed. Intramuscular immunization of C57BL/6 mice with this DNA vaccine resulted in successful induction of HBV-specific CTL responses. In order to promote transportation of the peptide into endoplasmic reticulum (ER) to bind to MHC class I molecules for optimal class I antigen presentation, an ER targeting sequence (ERTS) was fused with the C(18-27) encoding gene. ERTS fusion significantly enhanced specific CD8(+) T cell responses in terms of CTL cytolysis as well as IFN-gamma secretion. This enhancement was correlated with promoted epitope presentation on target cell surface. We report here an enhanced immunogenicity of an epitope-based DNA vaccine using an ER targeting signal sequence, which has significant implications for future design of therapeutic HBV vaccine.

Animals↗

PubMed2005

In silico analysis of disease-association mapping strategies using the coalescent process and incorporating ascertainment and selection.

We present a new method for simulating samples of marker haplotypes, genotypes, or diplotypes in case-control studies in which the markers are linked to a disease locus in any specified region of the genome. The method allows realistic features to be incorporated into the simulations, including selection acting on disease alleles, sample ascertainment of disease chromosomes and polymorphic markers, a genetic dominance model of disease expression that allows incomplete penetrance and phenocopies, and an accurate genetic map of recombination rates and hotspots for recombination in the human genome (or, alternatively, an improved method for simulating the distribution of hotspots). The new method uses an approach that combines simulation of the coalescent process for the sampled chromosomes with a diffusion process used to model the evolution of the disease-mutation frequency over time. Examples illustrate how the method may be used to study the expected power of a marker-disease association study.

Alleles↗

PubMed2005

Single B or T-cell epitope-based DNA vaccine using modified vector induces specific immune response against hepadnavirus.

Epitope-based DNA vaccine is an effective and powerful approach against a variety of pathogens or tumors. In present study, we reconstructed a vector that could effectively express short B and T-cell epitope of duck/hepatitis B virus, and investigated the role of the epitope-based DNA vaccination. The pUC19 was modified by inserting the compact transient framework (CTF), including HCMV IE1 promoter, enhancer, Kozak sequence, dual stop codon and 3' terminal bovine growth hormone terminal signal and so on. This modified vector was designated pEC(K) and supposed to effectively express short peptide. A well-defined single B-cell and T-cell epitope encoding gene of duck/hepatitis B virus has been synthesized as candidate epitope and cloned into pEC(K) plasmid, respectively. Transfection of the recombinant DNA into C(2)C(12) cell showed that modified plasmid could effectively express both the single B-cell and T-cell short epitope in the culture supernatant as confirmed by dot immunoblot assay (DIA). The recombinant single B and T-cell epitope-based DNA vaccine was administrated to C57BL/6 mice and could greatly induce specific humoral and CTL response. In addition, the specific antibody against B epitope could specifically bind to the DHBV particles. This report demonstrated that single epitope-based DNA vaccine using modified plasmid vector pEC(K) could induce effective specific immune responses and could be of great use for DNA vaccines.

Animals↗

PubMed2005

Differential regulation of cortactin and N-WASP-mediated actin polymerization by missing in metastasis (MIM) protein.

Missing in metastasis (MIM) gene encodes an actin binding protein that is expressed at low levels in a subset of malignant cell lines. MIM protein tagged by green fluorescent protein (GFP) colocalizes with cortactin, an Arp2/3 complex activator, and interacts directly with the SH3 domain of cortactin. Recombinant full-length MIM promotes markedly cortactin and Arp2/3 complex-mediated actin polymerization in an SH3 dependent manner. In contrast, MIM-CT, a short splicing variant of MIM, binds poorly to cortactin in vitro and is unable to enhance actin polymerization. Full-length MIM binds to G-actin with a similar affinity as N-WASP-VCA, a constitutively active form of N-WASP, and inhibits N-WASP-VCA-mediated actin polymerization as analysed in vitro. The significance of the association of MIM with cortactin and G-actin was evaluated in NIH3T3 cells expressing several MIM constructs. Overexpression of full-length wild-type MIM-GFP inhibited markedly the motility of NIH3T3 cells induced by PDGF and that of human vein umbilical endothelial cells induced by sphingosine 1 phosphate. However, an MIM mutant with deletion of the WH2 domain, which is responsible for G-actin binding, enhanced cell motility. The motility inhibition imposed by MIM was compromised in the cells overexpressing N-WASP. In contrast, deletion of an MIM proline-rich domain, which is required for an optimal binding to cortactin, substantiated the MIM-mediated inhibition of cell motility. These data imply that MIM regulates cell motility by modulating different Arp2/3 activators in a distinguished manner.

3T3 Cells↗

PubMed2005

Role of CYP2C9 and its variants (CYP2C93 and CYP2C913) in the metabolism of lornoxicam in humans.

CYP2C9 is an important member of the cytochrome P450 enzyme superfamily with some 12 CYP2C9 alleles (*1-*12) being previously reported. Recently, we identified a new CYP2C9 allele with a Leu90Pro mutation in a Chinese poor metabolizer of lornoxicam [Si D, Guo Y, Zhang Y, Yang L, Zhou H, and Zhong D (2004) Pharmacogenetics 14:465-469]. The new allele, designated CYP2C9*13, was found to occur in approximately 2% of the Chinese population. To examine enzymatic activity of the CYP2C9*13 allele, kinetic parameters for lornoxicam 5'-hydroxylation were determined in COS-7 cells transiently transfected with pcDNA3.1 plasmids carrying wild-type CYP2C9*1, variant CYP2C9*3, and CYP2C9*13 cDNA. The protein levels of cDNA-expressed CYP2C9*3 and *13 in postmitochondrial supernatant (S9) from transfected cells were lower than those from wild-type CYP2C9*1. Mean values of Km and Vmax for CYP2C9*1, *3, and *13 were 1.24, 1.61, and 2.79 microM and 0.83, 0.28, and 0.22 pmol/min/pmol, respectively. Intrinsic clearance values (Vmax/Km) for variant CYP2C9*3 and CYP2C9*13 on the basis of CYP2C9 protein levels were separately decreased to 28% and 12% compared with wild type. In a subsequent clinical study, the AUC of lornoxicam was increased by 1.9-fold and its oral clearance (CL/F) decreased by 44% in three CYP2C9*1/*13 subjects, compared with CYP2C9*1/*1 individuals. This suggests that the CYP2C9*13 allele is associated with decreased enzymatic activity both in vitro and in vivo.

Alleles↗

PubMed2005

Synthesis and electrochemical properties of vanadium pentoxide nanotube arrays.

Nanotube arrays of amorphous vanadium pentoxide (V(2)O(5)) were synthesized via template-based electrodeposition, and its electrochemical properties were investigated for Li-ion intercalation applications. The nanotubes have a length of 10 microm, outer diameter of 200 nm and inner diameter of 100 nm. Electrochemical analyses demonstrate that the V(2)O(5) nanotube array delivers a high initial capacity of 300 mAh/g, about twice that of the electrochemically prepared V(2)O(5) film. Although the V(2)O(5) nanotube array shows a more drastic degradation than the film under electrochemical redox cycles, the nanotube array reaches a stabilized capacity of 160 mAh/g, which remains about 1.3 times the stabilized capacity of the film.

Letter↗

PubMed2005

Rapid and efficient synthesis of 1,2,4-oxadiazoles utilizing polymer-supported reagents under microwave heating.

1,2,4-Oxadiazoles can be rapidly and efficiently synthesized from a variety of readily available carboxylic acids and amidoximes using either method A or method B. The use of commercially available polymer-supported reagents combined with microwave heating resulted in high yields and purities of the product 1,2,4-oxadiazoles in an expeditious manner. [structure: see text]

Carboxylic Acids↗

PubMed2005

Functional recovery in aged and young rats after embolic stroke: treatment with a phosphodiesterase type 5 inhibitor.

BACKGROUND AND PURPOSE: Advanced age is associated with a decrease in brain plasticity compared with the young adult. Sildenafil, a phosphodiesterase type 5 (PDE5) inhibitor promotes brain plasticity and improves functional outcome after stroke in the young animal. Here, we test the hypothesis that sildenafil provides restorative therapeutic benefit to the aged animal. METHODS: Male Wistar rats (aged, 18-month old; young, 3-month old) were subjected to embolic stroke. Saline or sildenafil was administered daily at a dose of 2 mg/kg orally or 10 mg/kg subcutaneously for 7 consecutive days starting 24 hour after stroke onset. RESULTS: Aged rats exhibited significant impairment of functional recovery and reductions of vascular density, and endothelial cell proliferation compared with young rats. Aged rats treated with sildenafil at a dose of 10 mg/kg but not 2 mg/kg, showed significant improvements of functional recovery and concomitant increases in cortical cyclic guanosine 3',5'-cyclic monophosphate (cGMP) level, vascular density, endothelial cell proliferation, and synaptogenesis compared with aged rats treated with saline. In young rats, treatment with sildenafil at a dose of 2 or 10 mg/kg significantly enhanced functional recovery and amplified brain plasticity compared with young rats treated with saline. CONCLUSIONS: Age is associated with reduction of angiogenesis, and poor neurological functional recovery after stroke. However, treatment of aged stroke rats with sildenafil improves functional recovery that is likely fostered by enhancement of angiogenesis and synaptogenesis.

3',5'-Cyclic-GMP Phosphodiesterases↗

PubMed2005

TEAVIGO (epigallocatechin gallate) supplementation prevents obesity in rodents by reducing adipose tissue mass.

BACKGROUND: This study investigated the antiobesity effects of TEAVIGO, a product providing the most abundant green tea catechin, epigallocatechin gallate (EGCG), in a pure form. Two models of diet-induced obesity and an in vitro adipocyte differentiation assay were employed. METHODS: Prevention and regression of diet-induced obesity by dietary supplementation with EGCG was studied in C57BL/6J mice and Sprague-Dawley rats, respectively. Expression of genes regulating lipid metabolism was assessed in adipose tissue. The effects of EGCG on adipocyte differentiation were investigated in vitro. RESULTS: In C57BL/6J mice, EGCG supplementation prevented diet-induced increases in body weight and in fed state plasma levels of glucose, triglycerides, and leptin. EGCG decreased subcutaneous and epididymal adipose tissue weights. Supplementation of EGCG reversed the established obesity in Sprague-Dawley rats. Fatty acid synthase and acetyl-CoA carboxylase-1 mRNA levels were markedly decreased in adipose tissue of EGCG-supplemented mice. EGCG dose dependently inhibited adipocyte differentiation in vitro. CONCLUSION: This study shows for the first time that supplementation with the most abundant green tea polyphenol, EGCG, abolishes diet-induced obesity. This effect is at least partly mediated via a direct influence on adipose tissue. Thus, dietary supplementation with EGCG should be considered as a valuable natural treatment option for obesity.

Adipose Tissue↗

PubMed2005

CKLFSF2 is highly expressed in testis and can be secreted into the seminiferous tubules.

CKLFSF2 is a member of the chemokine-like factor superfamily (CKLFSF), a novel gene family containing CKLF and CKLFSF1-8. Using a combination of data mining and polymerase chain reactions, we determined the full cDNA sequence and genomic structure of human CKLFSF2, a 4-exon gene encoding 248 amino acids and spanning approximately 8.8 kb on chromosome 16q22.1. Expression profile analyses indicated that CKLFSF2 is expressed in a limited number of tissues. Specifically, immunohistochemistry indicated that CKLFSF2 is highly expressed in testis, mainly in spermatogonia and the seminiferous tubular fluid. Subcellular localization experiments suggested that CKLFSF2 is equally distributed in the cytoplasm, and Western blot analysis revealed that overexpressed CKLFSF2 is secreted into the supernatant of cultured cells. The data therefore strongly suggest that CKLFSF2 is a secreted protein that may be functionally relevant during spermatogenesis.

Amino Acid Sequence↗

PubMed2005

Identification of a distal STAT5-binding DNA region that may mediate growth hormone regulation of insulin-like growth factor-I gene expression.

Growth hormone (GH) regulates insulin-like growth factor-I (IGF-I) gene expression through signal transducer and activator of transcription 5b (STAT5b) and STAT5a. The objective of this study was to identify the cis-regulatory DNA region involved in this process. By cotransfection analyses of shotgun DNA fragments of a bacterial artificial chromosome sequence containing the entire human IGF-I gene and a large 5'-flanking region, a approximately 700-bp DNA region approximately 75 kb 5' to the IGF-I gene was found to have the ability to enhance gene expression from both heterologous and homologous promoters in the presence of constitutively active STAT5a or STAT5b. This 700-bp DNA region contains two closely located consensus STAT5-binding sites, and its sequence appears to be evolutionarily conserved. Electrophoretic mobility shift assays verified the ability of the two putative STAT5-binding sites to bind to STAT5a and STAT5b. Cotransfection analyses confirmed that both STAT5-binding sites were necessary for the 700-bp DNA region to mediate STAT5a or STAT5b activation of gene transcription. Chromatin immunoprecipitation assays demonstrated that the chromosomal region containing these two STAT5-binding sites was bound by constitutively active STAT5b protein in HepG2 cells and that the binding was accompanied by increased expression of IGF-I mRNA. In reconstituted GH-responsive cells, this 700-bp DNA region was able to mediate GH-induced STAT5a or STAT5b activation of gene expression. These results together suggest that this STAT5-binding site-containing distal 5'-flanking region of IGF-I gene may be an enhancer mediating GH-induced STAT5 activation of IGF-I gene transcription.

5' Flanking Region↗

PubMed2005

A new layered zinc phosphate templated by protonated isonicotinate, [Zn2(C6H5NO2)2(HPO4)2].

An organic-inorganic hybrid compound, poly[bis[(pyridine-4-carboxylato)zinc(II)]-di-mu3-phosphato], [Zn2(C6H5NO2)2(HPO4)2], has been hydrothermally synthesized and structurally characterized. The crystal structure consists of two types of two-dimensional layers of zinc hydrogenphosphate templated by protonated isonicotinate (ina) (or 4-pyridinecarboxylic acid), which contain two crystallographically independent centrosymmetric [Zn2(ina)2(HPO4)2] dimers as basic building units. The layers are interconnected via hydrogen-bonding and heterocyclic ring interactions.

Crystallography, X-Ray↗

PubMed2005

Ni-V2O5.nH2O core-shell nanocable arrays for enhanced electrochemical intercalation.

We have prepared Ni-V(2)O(5).nH(2)O core-shell nanocable arrays for Li(+) intercalation applications. Ni-V(2)O(5).nH(2)O nanocables were prepared via formation of Ni nanorod arrays through the template based electrochemical deposition, followed by coating of V(2)O(5).nH(2)O on Ni nanorods through electrophoretic deposition. Transmission electron microscopy (TEM) micrograph clearly shows the Ni core was covered completely by a V(2)O(5).nH(2)O shell. Electrochemical analysis demonstrates that in a current density of 1.6 A/g, the Li(+) intercalation capacity of Ni-V(2)O(5).nH(2)O nanocable array is approximately 10 times higher than that of single-crystal V(2)O(5) nanorod array and 20 times higher than that of sol-gel-derived V(2)O(5) film. Both energy density and power density of such nanocable-array electrodes are higher than the V(2)O(5) film electrode by at least 1 order of magnitude. Such significant improvement in electrochemical performance is due to the large surface area and short diffusion path offered by the nanostructured V(2)O(5).nH(2)O.

Letter↗