Therapeutic Role for TSP-2 Antibody in a Murine Asthma Model.

BACKGROUND: Specific immunotherapy, including agonists for Toll-like receptor 2 (TLR2), have been shown to protect from allergies and to have a high immunomodulatory capacity. METHODS: A new antibody, TSP-2, reactive against an epitope of the extracellular domain of TLR2, was identified. The effect of the antibody on dendritic cells was assessed by immunohistochemistry, Western blot, and flow cytometric analysis. The effect of TSP-2 in a murine asthma model induced with ovalbumin (OVA) was assessed. The model is a form of airway hyperresponsiveness (AHR) and was analyzed by whole-body plethysmography, the measurement of Th1/Th2 cytokines in bronchial alveolar lavage fluid (BALF) and serum by ELISA, and the CCK-8 assay for lymphocyte proliferation. The effect of TSP-2 on the maturation of bone marrow-derived dendritic cells (BMDCs) was assessed by flow cytometric analysis. RESULTS: TSP-2 promoted the maturation of dendritic cells and the proliferation of lymphocyte in vitro and in vivo. The effect of TSP-2 on T helper 1 (Th1)/Th2 cytokine secretion was slightly more powerful than that of Pam3CSK4. TSP-2 antibody reduced AHR and OVA-specific IgE levels in allergic asthma. TSP-2 antibody also reduced lung inflammation and decreased leukocyte numbers in an OVA-sensitized and challenged asthma model. TSP-2 antibody increased OVA-stimulated I-A, CD80, CD86, and MHC-II levels on BMDCs. CONCLUSIONS: This study identifies a novel therapeutic strategy for AHR, which uses antibodies reactive against TLR2. It also provides theoretical evidence for the control of allergic asthma by targeting TLR2.

Antitumour effects on human colorectal carcinomas cells by stable silencing of phospholipase C-gamma 1 with lentivirus-delivered siRNA.

BACKGROUND: In most colorectal carcinomas, the level of phospholipase C (PLC)-gamma 1 expression is greatly elevated. Increased expression of PLC-gamma 1 may play an important role in colon carcinogenesis, but the mechanism is not well known. The aim of this study was to evaluate the role of PLC-gamma 1 in colon carcinogenesis by using recombinant lentivirus that stably suppressed the PLC-gamma 1 expression in human colorectal carcinoma LoVo cells. METHODS: Recombinant lentivirus producing PLC-gamma 1 siRNA were prepared. After LoVo cells were transduced by each lentivirus, stably transduced cells were selected by Blasticidin. The protein and mRNA expression of PLC-gamma 1 were examined by Western-blot and reverse transcription-polymerase chain reaction (RT-PCR) analysis, and the effects of the lentivirus on the cell adhesion, migration and apoptosis were analyzed. RESULTS: Stable LoVo cell line deficient in PLC-gamma 1, was established. Notably, PLC-gamma 1 was silenced without affecting the levels of other subtypes of PLC so that the role of PLC-gamma 1 in colon carcinogenesis could be examined. Silencing of endogenous PLC-gamma 1 resulted in efficient inhibition of the adhesion and migration of LoVo cells in vitro and a great increase of 5-fluorouracil induced apoptosis (30%-40%) of LoVo cells. CONCLUSIONS: PLC-gamma 1 may play an important role in metastasis and anti-apoptosis in human colorectal carcinomas.

Mathematical model of phosphatidylinositol-4,5-bisphosphate hydrolysis mediated by epidermal growth factor receptor generating diacylglycerol.

Phosphatidylinositol-4,5-bisphosphate (PIP2) is hydrolyzed in response to the tyrosine phosphorylation of the epidermal growth factor receptor (EGFR) and plays an important role in regulating cell proliferation and differentiation through the generation of second messengers diacylglycerol (DAG) and trisphosphate inositol (IP3) which lead to the activation of protein kinase C (PKC) and increased levels of intracellular calcium, respectively. In the paper, a mathematical model was established to simulate the accumulation of DAG due to PIP2 hydrolysis mediated by EGFR. Molecular mechanisms between DAG, PIP2, EGFR and phosphatidylinositol transfer protein (PITP) were explained successfully, and positive cooperativity which existed between phospholipase C-gamma1 (PLC-gamma1) and PIP2 was also explained. In the model the effects of parameters on simulation of PIP2 hydrolysis were analyzed and the efficacies of some molecular intervention strategies were predicted. To test the coherence between the model and the biological response to epidermal growth factor (EGF) in cells, the levels of DAG and the tyrosine phosphorylation-EGFRs in NIH3T3 mouse embryonic fibroblast (MEF) were determined by biochemical experiments which showed that the accumulation of DAG was a sigmoidal function of phosphorylation-EGFR concentration, and the consistency between the mathematical model and experimental results was confirmed. In brief, this mathematical model provided a new idea for the further study of the dynamic change of biological characteristics in inositol phospholipid hydrolysis, predicting the efficacy of molecular intervention and the relationship between the metabolisms of inositol phospholipid and other signal transduction pathways.

[Inhibition of phospholipase C gamma1 signaling pathway promotes apoptosis of human colorectal carcinoma cells].

OBJECTIVE: To investigate the effects of inhibiting phospholipase C gamma1 signaling pathway on the apoptosis of human colorectal carcinoma cells. METHODS: SW620 cells were treated with U73122 in vitro to inhibit the phospholipase C gamma1 signalling pathway and examined under light microscope and transmission electron microscope for analyzing changes in apoptotic behavior of the cells. MTT assay was used to evaluate the cell killing effects, and the percentage of apoptotic cells analyzed using flow cytometry. RESULTS: After inhibition of the phospholipase C gamma1 signaling pathway by U73122, SW620 cells exhibited obvious apoptotic morphology, the viable cells decreased dramatically, and the percentage of apoptotic cells rose to above 50%. CONCLUSION: Inhibition of phospholipase C gamma1 signaling pathway can induce apoptosis of human colorectal carcinoma cells.

[Analysis of ERG11 gene mutation in Candida albicans].

OBJECTIVE: To study the relationship between fluconazole (FCZ)-resistance of Candida albicans and the mutation of ERG11 gene encoding FCZ-targeted enzyme. METHOD: Three strains of FCZ-susceptible and 10 FCZ-resistent C. albicans were isolated from the urethra, vagina, oropharynx, respiratory tract, prostate secretion and blood samples. ERG11 gene was amplified by PCR using C.albicans genomic DNA extracts as the templates and the DNA sequences of the PCR products were determined and compared using BLAST and Clustal-W softwares. RESULTS: The comparison of ERG11 gene sequences identified mutations at 21 sites in 13 strains, including 17 same-sense and 4 missense mutations. Base substitutions at the sites of 348 bp and 383 bp resulting in D116E and K128T conversion may take place in both drug-resistant and drug-susceptible strains. The point mutation at the site of 1309 bp of FCZ-resistant strain may cause V437I change, and the base inversion at 1320 bp may give rise to A/C heterozygosity mutant of ERG11 gene, probably resulting in N440K conversion. CONCLUSION: FCZ-resistance of C. albicans may be associated with point mutations of V437I and N440K in ERG11 gene, but not with the point mutations of D166E and K128T.

Phospholipase C-gamma1 is required for survival in heat stress: involvement of protein kinase C-dependent Bcl-2 phosphorylation.

The consequences of heat-induced phospholipase C-gamma1 (PLC-gamma1) phosphorylation are not known. We investigated the role of PLC-gamma1 activation and its downstream targets during the cellular response to heat stress using mouse embryonic fibroblasts genetically deficient in PLC-gamma1 (Plcg1 null MEF) and its wild type (wt MEF) as models. Treatment of wt MEF with heat resulted in temperature- and heating duration-dependent tyrosine phosphorylation of PLC-gamma1. HSP70 synthesis and the activation of extracellular signal-regulated kinases 1/2 (ERK1/2) and c-Jun N-terminal protein kinase (JNK) increased equally following heat treatment in both cell lines. However, heat-induced protein kinase C (PKC) activation was dramatically reduced in Plcg1 null MEF compared with wt MEF. Importantly, the mitochondrial localization of PKCalpha, PKC-dependent phosphorylation of Bcl-2, and cell viability in Plcg1 null MEF following heat treatment, were significantly decreased compared with the wild type. Furthermore, pretreatment with bryostatin-1, a PKC activator, enhanced Bcl-2 phosphorylation and cellular resistance to heat-induced apoptosis in Plcg1 null MEF. Taken together, these results suggest that PLC-gamma1 activation enhances cell survival through the PKC-dependent phosphorylation of Bcl-2 during the cellular response to heat stress.

[Normal pregnancy in a woman having had a child with trisomy 21 syndrome before: application of preimplantation genetic diagnosis].

OBJECTIVE: To study the value of preimplantation genetic diagnosis (PGD) before pregnancy for couples who are exposed to high risk of trisomy 21 syndrome in their progenies to obtain birth of healthy child by in vitro fertilization procedures. METHODS: Conventional hormone replacement treatment with intracytoplasmic sperm injection (ISCI) was administered for ovum fertilization. One or two cells (blastomeres) were aspirated from the preimplantation embryo that had grown to 6 to 10 cells (day 3 post fertilization) for PGD with fluorescence in situ hybridization (FISH), and 3 embryos with normal chromosome were transferred into the uterus. RESULTS: PGD was carried out in a total of 8 embryos with valid diagnoses in 7, of which 6 were identified as normal embryos and 1 had trisomy 21 syndrome. Pregnancy was obtained that resulted in the birth of a healthy baby. CONCLUSION: Detection of chromosomal abnormalities such as trisomy 21 syndrome is feasible for PGD with FISH.

Expression of phospholipase-gamma1 in human fetal tissues.

OBJECTIVE: To investigate the expression of phospholipase C-gamma1(PLC-gamma1) in human fetal tissues. METHODS: Serial sections 5 &mgr;m in thickness were prepared from paraformadehyde-fixed and paraffin-embedded normal human fetal tissues including the cartilage, the cartilage membrane and the muscle tissues. The distribution of PLC-gamma1 expression was examined immunohistochemically in the sections. RESULTS: Immunoreactive PLC-gamma1 was readily detected in the cells of the cartilage, the cartilage membrane and the muscl tissues, which was largely confined within the cytoplasm. CONCLUSION: PLC-gamma1 is essential for the early development and cell proliferation of human embryos.

[Blocking with double- stranded RNA of the expression of Hes5 in rat bone marrow-derived neural stem cells].

OBJECTIVE: To examine the efficiency of exogenous small double-stranded RNA (dsRNA) in knocking down the gene expression at the post-transcription level, and investigate the factors that may influence the transfection. METHOD: The bone marrow stromal cells of SD rat were separated and cultured in vitro, followed by induction of the cells to evolve into neural stem cells using special culture medium prepared by our laboratory. Synthetic dsRNA was then transferred into the cells at varied concentrations, and the results were analyzed by Western blotting. RESULTS: The concentrations ranging from 200 to 300 nmol/L were optimal for specifically blocking the expression of Hes5, whereas the suitable concentrations for the cell survival were between 50 and 200 nmol/L. CONCLUSION: dsRNA is capable of triggering RNA interference in neural stem cells, and at appropriate concentration, it may specifically and effectively knock down endogenous gene expression without sacrificing the viability of the cells.

[Phospholipase C-gamma1 dynamic mRNA expression patterns in rats during early postnatal period].

OBJECTIVE: To investigate the expression of phospholipase C-gamma1 (PLCG1) mRNA in rats during early postnatal period. METHODS: Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the expression of PLCG1 mRNA in 28 samples extracted from the liver, lung, kidney and brain of rats aged 1, 3, 5, 7 days, and 2, 3, 5 weeks. Specific PLCG1 product and GAPDH product as the internal control were both amplified by RT-PCR, and the ratio of their integral optical density was calculated to estimate the relative mRNA expression of PLCG1. RESULTS: PLCG1 was expressed in rat liver, lung, kidney and brain at the 7 postnatal time points, and the expression varied significantly with time and between the different organs (P<0.01), virtually undetectable in the liver on postnatal day 1 and reaching the highest level in the brain tissues on postnatal day 7. CONCLUSION: The differences in PLCG1 expression in various organs and development periods suggest that PLCG1 is involved in cell proliferation and differentiation during the early development of rats.

[Fluconazole resistance in Candida albicans assayed by PCR fingerprinting with M13 prime].

OBJECTIVE: To understand the molecular and genetic mechanism underlying fluconazole resistance in Candida albicans by PCR fingerprinting with M13 primer. METHODS: Paper disc diffusion method was employed for assay of fluconazole resistance in 41 clinical isolates of Candida albicans, followed by PCR fingerprinting with M13 primer to study the gel patterns with cluster analysis using neighbor joining (NJ) method performed with RAPD200 software. RESULTS: Of the 41 clinical isolates, 11 strains (26.8%) were fluconazole-sensitive, 8 (19.5%) fluconazole-dependent and 22 (53.7%) fluconazole-resistance. Two to twelve bands could be observed among these strains, and the gel patterns revealed by cluster analysis were associated with the reactions of the strains against fluconazole and the location of infection. CONCLUSION: There is high prevalence of fluconazole resistance in clinical Candida albicans isolates, and PCR fingerprinting with M13 primer is convenient for assay of fluconazole resistance and molecular epidemiological study of Candida albicans.

[Hydrogen peroxide inhibits arsenic trioxide-induced apoptosis of Burkitt lymphoma cells].

OBJECTIVE: To examine the effects of hydrogen peroxide (H2O2) on arsenic trioxide (As2O3)-induced apoptosis of human Burkitt lymphoma cells and evaluate the value of fluorescence microscope in analyzing cellular apoptosis. METHODS: As2O3 was used to induce apoptosis in human Burkitt lymphoma cells BJAB, and the cellular changes were analyzed quantitatively using transmission electron microscope and fluorescence microscope after staining with Hoechst 33342/ propidium iodide (PI). RESULTS: Under fluorescence microscope and electron microscope, BJAB cells displayed chromatin aggregation, nuclear margination and fragmentation in response to As2O3 treatment. In the presence of relatively low levels of H2O2 (200 micromol/L), the cell death resulting from apoptosis was inhibited with pyknosis and necrosis becoming the major pathway, while As2O3 failed to induce cell apoptosis. The cells showed none of the typical markers of apoptosis nor any characteristic necrotic changes, and the nuclei exhibited condensation instead of swelling. In addition, the rate of cell death induced by As2O3 was decreased in the presence of H2O2. CONCLUSIONS: Low levels of H2O2 (200 micromol/L) inhibits As2O3-induced (at clinically achievable concentrations) apoptosis of the human malignant lymphoma cells. Fluorescence microscopy makes possible quantitative analysis of apoptosis, capable of distinguishing not only cell apoptosis from necrosis, but also membrane-intact from membrane-permeable apoptotic cells.

[Construction and identification of yeast expression vectors containing human platelet-derived growth factor B-chain gene].

OBJECTIVE: To investigate the expression efficiency of human platelet-derived growth factor B-chain (PDGF-B) gene in yeast and assess the activity of the expressed product. METHODS: A full-length complementary DNA of human PDGF-B gene was amplified from the total RNA extracted from human vascular endothelial cells using reverse transcription (RT)-PCR and then cloned into pGEM-T vector. The PCR products with specific primers were recombined into yeast expression plasmids pMETB or pMETalphaA, followed by identification with restriction endonuclease. RESULTS: The 578 bp fragment encoding mature PDGF-BB peptide with signal peptide and the 340 bp fragment without signal peptide were identified and verified by restriction endonuclease mapping and sequencing, and two yeast expression vectors pMETB-PDGFB(1) and pMETalphaA-PDGFB(2) were reconstructed. CONCLUSION: The yeast expression vectors containing human PDGF-B gene have been successfully constructed for further studies of gene expression in yeast.

[Mathematical model of epidermal growth factor receptor-mediated lipid phosphatidylinositol(4,5)-bisphosphate hydrolyzation by phospholipase C-gamma1 activity].

OBJECTIVE: To investigate the dynamic characteristics of lipid phosphatidylinositol (4,5)-bisphosphate (PIP(2)) in plasma membrane hydrolyzed by phospholipase C-gamma1 in epidermal growth factor receptor(EGFR)-mediated signal pathway. METHODS: A mathematical model based on the law of mass action was established with differential equations to simulate metabolizable pathway of PIP(2). RESULTS: Differential equations of the key product concentration during hydrolysis of PIP(2) were formulated, and the effects of the parameters on these hydrolyzed products analyzed. CONCLUSION: This mathematical model provides foundation for further investigation of the dynamic changes of biological characteristics and the relations between the key product concentrations in PIP2 hydrolysis.

Construction and identification of eukaryotic expression vector of human full-length PLCgamma1 gene.

OBJECTIVE: To construct the eukaryotic expression vector of human full-length PLCgamma1 gene for further study of the role of PLCgamma1 in cancer invasion. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) technique was used to amplify human full-length PLCgamma1 gene from MG63 cells with a pair of specific primers containing the restriction sites for HindIII and NotI. After purification, the product of RT-PCR was digested with HindIII and NotI before insertion into the corresponding sites of eukaryotic expression vector pLNCX2, yielding the recombinant plasmid pLNCX2/PLCgamma1. PCR, restriction endonuclease analysis and DNA sequencing were performed to identify the recombinant eukaryotic expression vector pLNCX2/PLCgamma1. RT-PCR and Western blotting were used to detect the expression of the PLCgamma1 gene in LoVo cells after transient transfection via Lipofectamine TM 2000. RESULTS: A 3 878-bp full-length PLCgamma1 gene fragment was successfully amplified by RT-PCR and inserted into eukaryotic expression vector pLNCX2. After digestion by HindIII and NotI, the recombinant eukaryotic expression vector pLNCX2/PLCgamma1 yielded a 3 878-bp fragment (PLCgamma1 gene) and a 6 100 bp fragment (vector). HindIII-BglII digestion was also done to verify the correctness of the recombinant plasmid, resulting in the identification of the fragments as expected. Sequencing analysis further confirmed the results. In addition, RT-PCR and Western blotting verified that the PLCgamma1 could overexpress in LoVo cells after transfection with recombinant eukaryotic expression vector pLNCX2/PLCgamma1. CONCLUSION: The recombinant eukaryotic expression vector pLNCX2/PLCgamma1 has been constructed successfully.

Antisense epidermal growth factor receptor (EGFR) transfection down-regulates EGFR expression and suppresses the malignant phenotype of human nasopharyngeal carcinoma CNE-2 cell line.

OBJECTIVE: To determine whether epidermal growth factor receptor (EGFR) expression contributes to tumor growth of poorly differentiated human nasopharyngeal carcinoma CNE-2 cell lines. METHODS: An expression vector containing a N-terminal fragment (1.35 kb) of human EGFR in the antisense orientation was transfected into CNE-2 cell lines via lipofectamine. The established clones resistant to G418 were isolated and characterized, and the tumor-inhibiting effect of antisense EGFR expression was evaluated in terms of tumor growth and metastasis at different time after subcutaneous inoculation into nude mice. RESULTS: Down-regulated EGFR expression in the cells with antisense vector transfection was demonstrated by ligand binding assay. The growth rate and the ability to grow in soft agarose of these antisense transfectants were also reduced. After inoculation into nude mice, EGFR antisense transfectants showed a longer latency period, slower tumor growth and lower metastatic rates to the lymph nodes and lung in comparison with the parental cells. CONCLUSIONS: These results suggest that these EGFR antisense cDNA-transfected CNE-2 cells are of value to further delineate the role of EGFR in the development and progression of nasopharyngeal carcinoma.

Arsenic trioxide-induced apoptosis of human malignant lymphoma cell lines and its mechanisms.

OBJECTIVE: To investigate the responses of human Burkitt lymphoma cells to arsenic trioxide (As2O3) and the possible mechanisms. METHODS: Epstein-Barr virus (EBV)-positive human B-lymphoma Raji cell line and EBV-negative human B-lymphoma BJAB cell line were used as in vitro models to assess the cell apoptosis by morphology and DNA agarose gel electrophoresis. Protein expression was analyzed using Western blotting. RESULTS: After 24-hour treatment with the 2, 5 and 10 micromol/L As2O3, the concentrations of As2O3 achievable in vivo, cell apoptosis was induced in human Burkitt lymphoma BJAB cells at the rates of 47.6%+/-4.8% (Mean+/-SD, n=3), 66.4%+/-5.1%, 87.0%+/-7.3% and at 35.5%+/-3.8%, 51.5%+/-6.2%, 62.2%+/-7.9% respectively in Raji cells, corresponding to the concentration of As2O3. EBV-infected Raji cell line was less sensitive to As2O3 than EBV-negative BJAB cell line (P<0.05). As2O3-induced apoptosis was accompanied by down-regulation of Bcl-xL protein expression and activation of apoptosis protein caspase-3, as identified by Western blotting. CONCLUSION: As2O3 exerts apoptosis-inducing effects on human Burkitt lymphoma cells through down-regulation of Bcl-xL protein expression and activation of apoptosis protein caspase-3, and may serve as a candidate therapeutic agent against malignant lymphoma for both systemic and local therapies.

[Ultracytochemical observation of the intracellular localization of H+-adenosine triphosphatase].

OBJECTIVE: To observe the ultracytochemical localization of H(+)-adenosine triphosphatase (H(+)-ATPase) in the cell organelles. METHODS: The localization of H(+)-ATPase in the cell organelles was observed in the hepatocytes and renal cells of Wistar rats using routine ultracytochemical methods. RESULTS: H(+)-ATPase activities were observed on the lysosomal membrane and nuclear envelope of the hepatocytes and proximal tubule epithelial cells of the nephron in Wistar rats. CONCLUSION: This finding supports the hypothesis that H(+)-ATPase (V-ATPase) is present on the plasma membrane and in the endomembrane system.

[Effect of TSP-2 antibody against a single epitope of mouse Toll-like receptor 2 extracellular domain on nuclear factor-kappa B and cytokine expression in the intestine of septic mice].

OBJECTIVE: To observe the effect of the antibody TSP-2 against a single epitope of mouse Toll-like receptor 2 extracellular domain (mTLR2ECD) on the expression of nuclear factor-kappa B (NF-κB) and cytokines in the intestinal tissue of septic mice. METHODS: Male BALB/c mice were randomly divided into 4 groups, namely the sham-operated group, model group, TSP-2 treatment group and rabbit IgG treatment group. Sepsis was induced by cecal ligation and puncture (CLP), and at 6, 12 or 24 h after the operation, the ileal tissues were harvested from the mice for HE staining. NF-κB expression was detected with immunohistochemistry. Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) mRNA expressions were detected with qRT-PCR and their protein expressions by ELISA. RESULTS: The NF-κB expression in the intestinal tissue significantly increased in the model group as compared with that in the sham- operated group, and decreased after TSP-2 treatment. The model group also showed significantly increased expression levels of TNF-α and IL-6 mRNA and protein in the intestinal tissue (P<0.05), which were lowered by TSP-2 (P<0.05) but not by rabbit IgG treatment (P>0.05). CONCLUSION: The TSP-2 antibody can protect the intestine and delay the development of sepsis by inhibiting NF-κB activation and down-regulating TNF-α and IL-6 expressions in mice.

[Establishment of molecular beacon real-time PCR for detecting p53 gene single nucleotide polymorphism].

OBJECTIVE: To establish a method based on molecular beacon real-time PCR for detecting single nucleotide polymorphisms (SNP) in codon 72 of scar-related p53 gene. METHODS: Two fluorescence-labeled molecular beacon probes were synthesized targeting CCC/CGC SNP of p53 codon 72. The genomic DNA was extracted from the peripheral blood of 28 patients with keloid, and the CCC/CGC SNP of P53 gene codon 72 were assayed with molecular beacon real-time PCR. The results of SNP typing were compared with the results of reverse dot hybridization and confirmed by direct DNA sequencing. RESULTS: The goodness of fit of this method was 100% in comparison with direct DNA sequencing, higher than that of reverse dot hybridization. CONCLUSION: Molecular beacon real-time PCR is suitable for rapid clinical detection of SNPs in p53 gene.