Biomedical subjects

Jian Huang

Publications and source records attributed to Jian Huang.

At least 55 records · Page 3Linked to original sources

PubMed2006

Contribution of C/EBP proteins to Epstein-Barr virus lytic gene expression and replication in epithelial cells.

The contribution of C/EBP proteins to Epstein-Barr virus (EBV) lytic gene expression and replication in epithelial cells was examined. Nasopharyngeal carcinoma cell lines constitutively expressed C/EBPbeta and had limited C/EBPalpha expression, while the AGS gastric cancer cell line expressed significant levels of both C/EBPalpha and C/EBPbeta. Induction of the lytic cycle in EBV-positive AGS/BX1 cells with phorbol ester and sodium butyrate treatment led to a transient stimulation of C/EBPbeta expression and a prolonged increase in C/EBPalpha expression. In AGS/BX1 cells, endogenous C/EBPalpha and C/EBPbeta proteins were detected associated with the ZTA and oriLyt promoters but not the RTA promoter. Electrophoretic mobility shift assays confirmed binding of C/EBP proteins to multiple sites in the ZTA and oriLyt promoters. The response of these promoters in reporter assays to transfected C/EBPalpha and C/EBPbeta proteins was consistent with the promoter binding assays and emphasized the relative importance of C/EBPs for activation of the ZTA promoter. Mutation of the oriLyt promoter proximal C/EBP site had little effect on ZTA activation of the promoter in a reporter assay. However, this mutation impaired oriLyt DNA replication, suggesting a separate replication-specific contribution for C/EBP proteins. Finally, the overall importance of C/EBP proteins for lytic gene expression was demonstrated using CHOP10 to antagonize C/EBP DNA binding activity. Introduction of CHOP10 significantly impaired induction of the ZTA, RTA, and BMRF1 proteins in chemically treated AGS/BX1 cells. Thus, C/EBPbeta and C/EBPalpha expression are associated with lytic induction in AGS cells, and expression of C/EBP proteins in epithelial cells may contribute to the tendency of these cells to exhibit constitutive low-level ZTA promoter activity.

Antigens, Viral↗

PubMed2006

Fibroblast growth factor-2 suppresses oridonin-induced L929 apoptosis through extracellular signal-regulated kinase-dependent and phosphatidylinositol 3-kinase-independent pathway.

Oridonin, isolated from Rabdosia rubescences, has been reported to exert cytotoxic effects on L929 cells. In this study, we investigated the mechanisms of FGF-2 protection of L929 cells from oridonin-induced apoptosis. Phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB) signal did not mediate this effect because the PI3K inhibitor wortmannin failed to reverse this protection and PKB activation was not observed in this process. In contrast, the extracellular signal-regulated kinase (ERK) was responsible for this rescue because its inhibition abolished the protective effect of fibroblast growth factor (FGF)-2. ERK had dual regulatory functions: mediating cell apoptosis or preventing cells from initiating the apoptotic response by phosphorylation or promoting expression of Bcl-2 in dependence of different stimuli. In L929 cells treated with oridonin alone, the activated ERK decreased the ratio of Bcl-2/Bax by mediating the phosphorylation of Bcl-2, resulting in apoptosis; the Ras inhibitor manumycin A and Raf inhibitor GW5074 failed to inhibit this apoptosis, indicating that there is a signal other than Ras/Raf pathway activated ERK. However, in the presence of FGF-2, Bcl-2 phosphorylation was blocked, and the Ras/Raf/ERK signal pathway was activated and protected against the oridonin-induced apoptosis by the alternative function of promoting of Bcl-2 expression.

Animals↗

PubMed2006

[Sequence variation of chloroplast gene infA-rpl36 region occurred in some Triticeae species].

Based on the sequenced wheat chloroplast genome (cpDNA), a pair of primers in infA-rp136 region was designed and used to amplify DNA from 12 diploid or polyploid Triticeae species. The 12 PCR products were cloned and sequenced. The resulting sequences ranged from 584 to 601 bp. DNA sequence analysis revealed that variation was higher in their intergenic regions than in their coding regions. Among these 12 species, the DNA sequence of coding region of infA gene showed homology as high as 97 percent, indicating that the infA gene is highly conserved among species. However, substantial deletions and insertions were found in 5 out of 12 deduced amino acid sequences, confirming that infA is one of the most evolutionally active cpDNA genes. Whereas the low variation was observed in rp136 gene, implying that the different genes has different evolutionary speed. The constructed phylogenetic trees demonstrate that the polyploidy species Thinopyrum intermedium might have different origin of cytoplasm, and their cytoplasm origins are as complex as their nuclear genome origins.

Amino Acid Sequence↗

PubMed2006

Development and clinical evaluation of oligonucleotide microarray for HLA-AB genotyping.

BACKGROUND: The antigens encoded by human leukocyte antigen (HLA) genes are primary antigens in immunological response of transplantation, and genotypes of HLA-A, B and DRB1 must be determined on donors and recipients before the transplantation is carried out. In this study, oligonucleotide microarray for HLA-AB genotyping was prepared and evaluated. METHODS: Oligonucleotide probes were designed based on the sequence of the different genotypes of HLA-A and B and were fixed on silylated glass slides to form a microarray. Fluorescence-labeled target DNA was obtained by asymmetric polymerase chain reaction amplification of exon 2 and exon 3 of HLA-A and -B genes and hybridized to the microarray. The hybridized microarray was subsequently scanned and the result was analyzed by software in order to determine the genotypes of the tested sample. RESULTS: The sensitivity of the microarray for HLA-AB genotyping was 10 ng/microl, with a coincidence rate of 100% with international reference, and a combined variation value of detected signal below 15%. Analysis of genotyping of 1295 cases of clinical samples showed that the general coincidence rate between the microarray method and conventional method (polymerase chain reaction-sequence-specific primer and flow cytometry reverse polymerase chain reaction sequence-specific oligonucleotide) was HLA-A: 99.61% and HLA-B: 98.30%, respectively. A total of five out of seven samples that had conflicting results of genotypes were proved to be microarray-assay reliable by DNA sequencing, suggesting a higher accuracy of the microarray method. CONCLUSION: The microarray for HLA-AB genotyping is satisfactory for clinical use in HLA-AB genotyping with its good specificity, sensitivity and reproducibility.

DNA Probes↗

PubMed2006

[WT1 gene expression in myelodysplastic syndrome and its clinical implication].

OBJECTIVE: To investigate the expression of WT1 gene in myelodysplastic syndrome (MDS) and to explore its clinical implications. METHODS: Expression of WT1 mRNA was detected in 53 patients with myelodysplastic syndrome and 10 healthy subjects by reverse transcriptase polymerase chain reaction (RT-PCR). RESULT: WT1 gene was expressed in all MDS patients. The positive rate and expression level in MDS patients were higher than those in healthy subjects. The positive rates of WT1 expression in MDS-RAEB and MDS-RAEB-t groups were higher than those in MDS-RA and MDS-RAS groups. The expression level was gradually increased from MDS-RA and MDS-RAS groups to MDS-RAEB and MDS-RAEB-t groups. CONCLUSION: The expression of WT1 gene might be associated with the development of MDS, and it can be used for risk assessment and monitor of disease progression and therapeutic effects in MDS patients.

Adolescent↗

PubMed2006

[Capillary zone electrophoretic determination of NaFeEDTA in iron fortified soy sauce].

OBJECTIVE: An analytical method for separation and determination of sodium iron (III) ethylenediaminetetraacetate (NaFeEDTA) in iron fortified soy sauce by capillary zone electrophoresis (CZE) has been developed. METHODS: The electrolyte, which contains 30 mmol/L citric acid, 20 mmol/L Tris, 0.15 mmol/L CTAB and 0.05 mmol/L SDS, was used to improve the peak shape and reduce the retention time at the voltage of - 25.0 kV. The sample can be determined at UV 254 nm after diluted. RESULTS: In this method, which enjoyed a wide linear range and good precision, the RSD (n = 6) was 2.15%, the average recoveries for samples ranged from 94.3% - 101.2% and the detection limit of the NaFeEDTA in iron fortified soy sauce is 4 microg/ml (S/N = 3). CONCLUSION: The results of application of different kinds of soy sauce showed that the method was direct, accurate, fast and simple.

Anemia, Iron-Deficiency↗

PubMed2006

[Determination of sodium iron (III) ethylenediaminetetraacetate in iron-fortified soy sauce by reversed-phase ion-pair high performance liquid chromatography].

A novel reversed-phase ion-pair high performance liquid chromatographic method was developed for separation and determination of sodium iron (III) ethylenediaminetetraacetate (NaFeEDTA) in iron-fortified soy sauce. Sample treatment and chromatographic conditions were investigated. After precipitation by methanol, the sample was separated on a Zorbax C8 column (150 mm x 4.6 mm i. d., 5 microm). The mobile phase was 12.5% (v/v) methanol solution containing 0.13% (v/v) tetrabutyl ammonium hydroxide and 0.052% (v/v) formic acid ( pH 3.5). NaFeEDTA was detected at 254 nm. The separation was achieved within 30 min with a flow rate of 1.00 mL/min. An iron-fortified soy sauce sample containing 2.00 g/L NaFeEDTA was analyzed for 6 times, and the relative standard deviation (RSD) of peak areas of NaFeEDTA was 0. 89%. The recoveries of NaFeEDTA ranged from 94.15% to 101.5% with the spiked amounts of 0.50 - 4.00 g/L. The detection limit of NaFeEDTA standard solution was 0.03 mg/L. This simple and rapid method with good reproducibility can be used for the determination of NaFeEDTA in iron-fortified soy sauce.

Anemia, Iron-Deficiency↗

PubMed2006

[Effect of KLF6 on prostate cancer cell line PC-3 by transgenic method].

OBJECTIVE: To observe the effect of KLF6 on prostate cancer cell line PC-3 by transgenic method. METHODS: We obtained KLF6 cDNA by RT-PCR method from the liver cell, transfected plasmid pEGFP-C, recombinated with KLF6 into PC-3 cells, and used them as a transfection group and a control group. MTT, flow cytometer and immunocytochemical methods were used to observe the effect of anti-oncogene wild type KLF6 on prostate cancer cell line PC-3 by transgenic method for 48 hours. RESULTS: After transfected into PC-3 cells, KLF6 enhanced growth suppression, (30.0 +/- 5.4)% in the transfection group and 0% in the control, P < 0.01, apoptosis, (24.3 +/- 2.3)% in the transfection group and (5.2 +/- 0.7)% in the control, P < 0.01, the down-regulation of the expression of cyclin D1, (25.3 +/- 3.7)% in the transfection group and (38.5 +/- 4.6)% in the control, P < 0.05 and Bcl-2, (18.7 +/- 3.2)% in the transfection group, and (41.8 +/- 5.9)% in the control, P < 0.01 in PC-3 cells. It also decreased the ratio of the cell phase G2/M, increased the ratio of G0/G1 from (58.6 +/- 7.3)% in the control to (80.0 +/- 9.8)% in the transfection group, P < 0.05. CONCLUSION: PC-3 cells transfected with wild type KLF6 can enhance its growth suppression and apoptosis. It shows great potential for the gene therapy of androgen-independent carcinoma of the prostate.

Apoptosis↗

PubMed2006

CD40/CD40L dyad in the inflammatory and immune responses in the central nervous system.

CD40 and its cognate ligand (CD40L) are a pair of regulators of pro-inflammatory and immune responses. In the central nervous system (CNS), CD40 is expressed on a variety of cells, including vascular endothelial cells, smooth muscle cells, astrocytes and microglia (the brain macrophages, being the most sensitive cell type to respond to CD40 ligand). Interaction between CD40 on microglia and CD40L presented by infiltrating T lymphocytes and other resident CNS cells triggers a series of intracellular signaling events that promote the production of a wide array of cytokines, chemokines and neurotoxins. Thus, both molecules serve as amplifiers of pro-inflammatory and immune responses in the CNS and constitute important molecular targets for therapeutic intervention of diseases.

Alzheimer Disease↗

PubMed2006

[Replacement of the constant region gene of a novel anti-CEA antibody and characterization of its biological activity].

AIM: To convert the subclass of a novel anti-CEA antibody, C2-45, from IgG4 to IgG1, and to increase its biological activity. METHODS: V(H) and V(kappa); genes were cloned from C2-45(IgG4), then inserted to pAc-kappa-CH3 expression vector which contained the constant region gene of human IgG1. The recombinant gene was transfected to Sf9 insect cells to produce recombinant virus with high titer and obtain recombinant protein. The recombinant protein, in the culture supernatant, designated C2-45 (IgG1), was purified by affinity chromatography, and characterized for the CEA binding specificity and the biological activity of CDC and ADCC. RESULTS: The C2-45 (IgG1), retained the original antigen-binding activity and effectively introduced a specific cytotoxicity of complement and lymphokine-activated killer cells to the CEA-expressing tumor cells. CONCLUSION: The constant region of anti-CEA antibody C2-45 was successfully converted from IgG4 to IgG1, which may be useful for immunotherapy of human CEA-expressing tumors.

Animals↗

PubMed2006

[Experimental study on the effects of jujingwan on oligospermia].

OBJECTIVE: To investigate the effects of Jujingwan on the spermatozoal ultrastructure and apoptosis of germ cells in oligospermia patients. METHODS: We treated 50 oligospermia patients with Jujingwan and observed the spermatozoal ultrastructure, the apoptosis of germ cells and the changes in the DNA ploidy proportion of spermatogenic cells by electron microscopy and FCM before the treatment and 3, 6, 9 and 12 months after it. RESULTS: Jujingwan increased sperm acrosome base density 6 months after the treatment and remarkably improved the integrity of acrosome membrane 12 months after it, with no obvious pathological changes in the nuclei and tails. Three months after the treatment, cell debris and apoptotic cells decreased significantly as compared with pre-treatment (P < 0. 05) , and very significantly 12 months after the treatment (P <0. 01). The proportion of haploid spermatozoa increased very significantly (P <0.01) , and the lost primary spermatocytes decreased significantly (P <0. 05) compared with pre-treatment. CONCLUSION: Jujingwan can increase the density of sperm acrosome base and improve the pathological changes of acrosome membrane in oligospermia patients; it can improve the activity of acrosome enzyme and the integrity of acrosome membrane, decrease the apoptosis rate of germ cells and sperm and increase the percentage of haploid spermatozoa; it can also reduce the percentage of apoptotic bodies and diploid sperm cells. It is indicated that Jujingwan can inhibit the apoptosis of germ cells and sperm and improve spermatogenesis in oligospermia patients.

Acrosome↗

PubMed2005

Bovine adrenal medulla 22 reverses antinociceptive morphine tolerance in the rat.

Acute intrathecal (i.t.) bovine adrenal medulla 22 (BAM22, 10 nmol), an endogenous opioid peptide, induced equipotent thermal antinociception in naïve and morphine-tolerant rats while chronic BAM22 resulted in hyperalgesia and decrease in the effectiveness of antinociception. In rats made tolerant to morphine, prior administration of BAM22 (10 nmol, i.t.) significantly resumed antinociceptive response of morphine. The present study demonstrated that BAM22 was able to modulate maintenance of morphine tolerance.

Algorithms↗

PubMed2005

ATP-dependent chromatin-remodeling complexes in DNA double-strand break repair: remodeling, pairing and (re)pairing.

The genomic integrity of a eukaryotic cell is challenged by over 10,000 chromosomal lesions per day. Therefore the cell has evolved efficient mechanisms to recognize, signal, and repair DNA breaks. Defects in any of these steps can lead to chromosomal aberrations and cancers. As these lesions must be repaired in the context of chromatin, both chromatin-modifying and nucleosome-remodeling enzymes have been implicated in DNA damage repair. We reported recently that the RSC and Swi/Snf ATP-dependent chromatin-remodeling complexes are involved in DSB repair specifically by homologous recombination. Here we discuss how such enzymes might be recruited to DNA breaks, why so many remodelers are recruited to sites of DSBs, and a possible functional connection between RSC's roles in sister chromatid cohesion and DSB repair.

Adenosine Triphosphatases↗

PubMed2005

TAp63alpha induces AP-2gamma as an early event in epidermal morphogenesis.

Epidermal morphogenesis begins with the commitment of the single-layered surface ectoderm to initiate a stratification program, a process that requires the expression of the transcription factor TAp63alpha. To determine the molecular mechanism by which TAp63alpha induces genes associated with the commitment to stratification, such as K14, we have used a combination of in vitro and in vivo approaches. Our initial gene expression profiling studies suggested that TAp63alpha could regulate one or more AP-2 genes, which have been implicated in development and maintenance of the epidermis. We now demonstrate that TAp63alpha directly induces AP-2gamma expression in embryonic epidermis, when commitment to stratification occurs. Furthermore, we show that, in the absence of AP-2gamma, TAp63alpha fails to induce K14 expression in vitro. Our data identify AP-2gamma as the first in vivo target gene of TAp63alpha, and provide novel insights into the molecular mechanisms associated with early events in epidermal morphogenesis.

Animals↗

PubMed2005

Myosin light chain kinase and myosin phosphorylation effect frequency-dependent potentiation of skeletal muscle contraction.

Repetitive stimulation potentiates contractile tension of fast-twitch skeletal muscle. We examined the role of myosin regulatory light chain (RLC) phosphorylation in this physiological response by ablating Ca(2+)/calmodulin-dependent skeletal muscle myosin light chain kinase (MLCK) gene expression. Western blot and quantitative-PCR showed that MLCK is expressed predominantly in fast-twitch skeletal muscle fibers with insignificant amounts in heart and smooth muscle. In contrast, smooth muscle MLCK had a more ubiquitous tissue distribution, with the greatest expression observed in smooth muscle tissue. Ablation of the MYLK2 gene in mice resulted in loss of skeletal muscle MLCK expression, with no change in smooth muscle MLCK expression. In isolated fast-twitch skeletal muscles from these knockout mice, there was no significant increase in RLC phosphorylation in response to repetitive electrical stimulation. Furthermore, isometric twitch-tension potentiation after a brief tetanus (posttetanic twitch potentiation) or low-frequency twitch potentiation (staircase) was attenuated relative to responses in muscles from wild-type mice. Interestingly, the site of phosphorylation of the small amount of monophosphorylated RLC in the knockout mice was the same site phosphorylated by MLCK, indicating a potential alternative signaling pathway affecting contractile potentiation. Loss of skeletal muscle MLCK expression had no effect on cardiac RLC phosphorylation. These results identify myosin light chain phosphorylation by the dedicated skeletal muscle Ca(2+)/calmodulin-dependent MLCK as a primary biochemical mechanism for tension potentiation due to repetitive stimulation in fast-twitch skeletal muscle.

Animals↗

PubMed2005

Regularized ROC method for disease classification and biomarker selection with microarray data.

MOTIVATION: An important application of microarrays is to discover genomic biomarkers, among tens of thousands of genes assayed, for disease classification. Thus there is a need for developing statistical methods that can efficiently use such high-throughput genomic data, select biomarkers with discriminant power and construct classification rules. The ROC (receiver operator characteristic) technique has been widely used in disease classification with low-dimensional biomarkers because (1) it does not assume a parametric form of the class probability as required for example in the logistic regression method; (2) it accommodates case-control designs and (3) it allows treating false positives and false negatives differently. However, due to computational difficulties, the ROC-based classification has not been used with microarray data. Moreover, the standard ROC technique does not incorporate built-in biomarker selection. RESULTS: We propose a novel method for biomarker selection and classification using the ROC technique for microarray data. The proposed method uses a sigmoid approximation to the area under the ROC curve as the objective function for classification and the threshold gradient descent regularization method for estimation and biomarker selection. Tuning parameter selection based on the V-fold cross validation and predictive performance evaluation are also investigated. The proposed approach is demonstrated with a simulation study, the Colon data and the Estrogen data. The proposed approach yields parsimonious models with excellent classification performance.

Algorithms↗

PubMed2005

Nitric oxide sensitizes tumor cells to dendritic cell-mediated apoptosis, uptake, and cross-presentation.

Dendritic cells are professional antigen-presenting cells associated with efficient antigen processing and presentation to T cells. However, recent evidence also suggests that dendritic cells may mediate direct tumoricidal functions. In this study, we investigated the mechanism by which murine dendritic cells mediate the apoptotic death of murine lymphoma cell lines, and whether dendritic cell effector function could be enhanced by preconditioning tumor cells with the protein phosphatase inhibitor nitric oxide (NO) by altering the balance of proapoptotic/antiapoptotic proteins in the treated cells. We observed that NO donor compound sensitized lymphomas to dendritic cell-mediated cytotoxicity in vitro. Both immature and spontaneously matured bone marrow-derived dendritic cells (SM-DC) were capable of inducing tumor cell apoptosis, with SM-DCs serving as comparatively better killers. Fas ligand (FasL)-Fas engagement proved important in this activity because elevated expression of membrane-bound FasL was detected on SM-DCs, and dendritic cells derived from FasL-deficient mice were less capable of killing NO-sensitized tumor cells than wild-type dendritic cells. As FasL-deficient dendritic cells were still capable of mediating a residual degree of tumor killing, this suggests that FasL-independent mechanisms of apoptosis are also involved in dendritic cell-mediated tumor killing. Because NO-treated tumor cells displayed a preferential loss of survivin protein expression via a proteasome-dependent pathway, enhanced tumor sensitivity to dendritic cell-mediated killing may be associated with the accelerated turnover of this critical antiapoptotic gene product. Importantly, NO-treated tumor cells were also engulfed more readily than control tumor cells and this resulted in enhanced cross-presentation of tumor-associated antigens to specific T cells in vitro.

Animals↗

PubMed2005

Distinct roles for the RSC and Swi/Snf ATP-dependent chromatin remodelers in DNA double-strand break repair.

The failure of cells to repair damaged DNA can result in genomic instability and cancer. To efficiently repair chromosomal DNA lesions, the repair machinery must gain access to the damaged DNA in the context of chromatin. Here we report that both the RSC and Swi/Snf ATP-dependent chromatin-remodeling complexes play key roles in double-strand break (DSB) repair, specifically by homologous recombination (HR). RSC and Swi/Snf are each recruited to an in vivo DSB site but with distinct kinetics. We show that Swi/Snf is required earlier, at or preceding the strand invasion step of HR, while RSC is required following synapsis for completion of the recombinational repair event.

Adenosine Triphosphate↗