Genomic DNA hypomethylation is associated with neural tube defects induced by methotrexate inhibition of folate metabolism

DNA methylation is thought to be involved in the etiology of neural tube defects (NTDs). However, the exact mechanism between DNA methylation and NTDs remains unclear. Herein, we investigated the change of methylation in mouse model of NTDs associated with folate dysmetabolism by use of ultraperformance liquid chromatography tandem mass spectrometry (UPLC/MS/MS), liquid chromatography-electrospray ionization tandem mass spectrometry (LC-MS/MS), microarray, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and Real time quantitative PCR. Results showed that NTD neural tube tissues had lower concentrations of 5-methyltetrahydrofolate (5-MeTHF, P = 0.005), 5-formyltetrahydrofolate (5-FoTHF, P = 0.040), S-adenosylmethionine (SAM, P = 0.004) and higher concentrations of folic acid (P = 0.041), homocysteine (Hcy, P = 0.006) and S-adenosylhomocysteine (SAH, P = 0.045) compared to control. Methylation levels of genomic DNA decreased significantly in the embryonic neural tube tissue of NTD samples. 132 differentially methylated regions (35 low methylated regions and 97 high methylated regions) were selected by microarray. Two genes (Siah1b, Prkx) in Wnt signal pathway demonstrated lower methylated regions (peak) and higher expression in NTDs (P<0.05; P<0.05). Results suggest that DNA hypomethylation was one of the possible epigenetic variations correlated with the occurrence of NTDs induced by folate dysmetabolism and that Siah1b, Prkx in Wnt pathway may be candidate genes for NTDs.

PRMT5 enhances generation of induced pluripotent stem cells from dairy goat embryonic fibroblasts via down-regulation of p53

OBJECTIVES

Protein arginine methyltransferase 5 (PRMT5), is thought to play a role in epigenetic reprogramming of mouse germ cells. However, up to now there has been little information concerning its expression profile and effects on generation of induced pluripotent stem cells (iPSCs) from somatic cells, in livestock. Here, we have explored PRMT5 expression profiles in dairy goats and its consequences to derivation of iPSCs from dairy goat embryonic fibroblasts (GEFs).

MATERIALS AND METHODS

We investigated effects of PRMT5 on iPS-like cells production in vitro. alkaline phosphatase (AP) staining, QRT-PCR and western blotting analysis of expression of related markers were used to evaluate efficiency of generation of iPSCs derived from GEFs.

RESULTS

These showed PRMT5 to be a conservative gene widely expressed in various tissues and different-aged testes. PRMT5 overexpression in combination with OCT3/4, SOX2, KLF4 and C-MYC (POSKM) significantly increased number of AP positive iPS-like colony-derived GEFs compared to OSKM alone, in our dairy goats. Moreover, our results demonstrated that PRMT5 overexpression stimulated GEF proliferation and down-regulated p53, p21 (a target gene of p53) and the apoptotic marker caspase 3, to enhance somatic cell reprogramming.

CONCLUSION

This study provides an efficient model for future studies on mechanisms underlying goat somatic cell reprogramming and differentiation.

dNTP deficiency induced by HU via inhibiting ribonucleotide reductase affects neural tube development

Exposure to environmental toxic chemicals in utero during the neural tube development period can cause developmental disorders. To evaluate the disruption of neural tube development programming, the murine neural tube defects (NTDs) model was induced by interrupting folate metabolism using methotrexate in our previous study. The present study aimed to examine the effects of dNTP deficiency induced by hydroxyurea (HU), a specific ribonucleotide reductase (RNR) inhibitor, during murine neural tube development. Pregnant C57BL/6J mice were intraperitoneally injected with various doses of HU on gestation day (GD) 7.5, and the embryos were checked on GD 11.5. RNR activity and deoxynucleoside triphosphate (dNTP) levels were measured in the optimal dose. Additionally, DNA damage was examined by comet analysis and terminal deoxynucleotidyl transferase mediated dUTP nick end-labeling (TUNEL) assay. Cellular behaviors in NTDs embryos were evaluated with phosphorylation of histone H3 (PH-3) and caspase-3 using immunohistochemistry and western blot analysis. The results showed that NTDs were observed mostly with HU treatment at an optimal dose of 225 mg/kg b/w. RNR activity was inhibited and dNTP levels were decreased in HU-treated embryos with NTDs. Additionally, increased DNA damage, decreased proliferation, and increased caspase-3 were significant in NTDs embryos compared to the controls. Results indicated that HU induced murine NTDs model by disturbing dNTP metabolism and further led to the abnormal cell balance between proliferation and apoptosis.

Raltitrexed's effect on the development of neural tube defects in mice is associated with DNA damage, apoptosis, and proliferation

The causal metabolic pathway and the underlying mechanism between folate deficiency and neural tube defects (NTDs) remain obscure. Thymidylate (dTMP) is catalyzed by thymidylate synthase (TS) using the folate-derived one-carbon unit as the sole methyl donor. This study aims to examine the role of dTMP biosynthesis in the development of neural tube in mice by inhibition of TS via a specific inhibitor, raltitrexed (RTX). Pregnant mice were intraperitoneally injected with various doses of RTX on gestational day 7.5, and embryos were examined for the presence of NTDs on gestational day 11.5. TS activity and changes of dUMP and dTMP levels were measured following RTX treatment at the optimal dose. DNA damage was determined by detection of phosphorylated replication protein A2 (RPA2) and γ-H2AX in embryos with NTDs induced by RTX. Besides, apoptosis and proliferation were also analyzed in RTX-treated embryos with NTDs. We found that NTDs were highly occurred by the treatment of RTX at the optimal dose of 11.5 mg/kg b/w. RTX treatment significantly inhibited TS activity. Meanwhile, dTMP was decreased associated with the accumulation of dUMP in RTX-treated embryos. Phosphorylated RPA2 and γ-H2AX were significantly increased in RTX-treated embryos with NTDs compared to control. More apoptosis and decreased proliferation were also found in embryos with NTDs induced by RTX. These results indicate that impairment of dTMP biosynthesis caused by RTX led to the development of NTDs in mice. DNA damage and imbalance between apoptosis and proliferation may be potential mechanisms.

Impact of TREM-2 gene silencing on inflammatory response of endotoxin-induced acute lung injury in mice

Acute lung injury (ALI) is one of the critical clinical respiratory diseases, of which infection is the main cause and the first risk factor. This study investigated the impact of triggering receptor of myeloid cells expression (TREM)-2 gene silencing on inflammatory response of endotoxin-induced ALI in mice. Lentivirus-mediated TREM-2-shRNA was transfected into healthy male C57BL/6 mice, and the lipopolysaccharide-induced ALI model was established. The immunohistochemistry, immunofluorescence, fluorescence quantitative PCR, western blot, and ELISA were applied to detect the pathological changes of lung tissue and expressions of TREM-2, tumor necrosis factor-α (TNF-α), and interleukin 10 (IL-10) in bronchoalveolar lavage fluid. The lentivirus group, saline control group, ALI model group, blank control group, and negative control group were set up at the same time. Results found that, in lentivirus group, the pathological change of lung tissue was significantly lighter than ALI model group (P < 0.05), and the expression of TREM-2 was significantly reduced compared with all control groups (P < 0.05). The levels of TNF-α and IL-10 were significantly increased than all control groups (P < 0.05), while above indexes in negative control group and blank control group showed no significant difference with ALI group (P > 0.05). This study indicates that TREM-2 has a protective effect on inflammatory response of endotoxin-induced ALI in mice, which has provided new potential targets for prevention and treatment of ALI.

Purification and characterization of a novel earthworm DNase

A new deoxyribonuclease (DNase), referred to as EWDNase, was isolated from earthworm tissues. The purification protocol included acetone precipitation, chromatography on CM-Sepharose, and gel electrophoresis. The overall purification was 73-fold with a recovery rate of 2.3% and a final specific activity of 2039 U/mg. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis suggested a molecular mass of 30 kD for EWDNase, with an isoelectric point of approximately 7.0. Maximum activity was detected at a pH of 5.6 and a temperature of 40°C. Addition of Mg(2+) and Ca(2+) ions promoted enzyme activity strongly, while Zn(2+) and ethylenediamine tetraacetic acid (EDTA) acted as inhibitors. Liquid chromatography-tandem mass spectroscopy (LC-MS/MS) analysis indicated that there was no known matching sequence. The properties of EWDNase were sufficiently different from previously reported enzymes to suggest that it is a new enzyme requiring further confirmation and characterization.

Quantification of folate metabolites in serum using ultraperformance liquid chromatography tandem mass spectrometry

Folate deficiency is considered a risk factor for many diseases such as cancer, congenital heart disease and neural tube defects (NTDs). There is a pressing need for more methods of detecting folate and its main metabolites in the human body. Here, we developed a simple, fast and sensitive ultraperformance liquid chromatography tandem mass spectrometry (UPLC/MS/MS) method for the simultaneous quantifications of folate metabolites including folic acid, 5-methyltetrahydrofolate (5-MeTHF), 5-formyltetrahydrofolate (5-FoTHF), homocysteine (Hcy), S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH). The method was validated by determining the linearity (r(2)>0.998), sensitivity (limit of detection ranged from 0.05 to 0.200ng/mL), intra- and inter-day precision (both CV<6%) and recovery (each analyte was >90%). The total analysis time was 7min. Serum samples of NTD-affected pregnancies and controls from a NTD high-risk area in China were analyzed by this method, the NTD serum samples showed lower concentrations of 5-MeTHF (P<0.05) and 5-FoTHF (P<0.05), and higher concentrations of Hcy (P<0.05) and SAH (P<0.05) compared with serum samples from controls, consistent with a previous study. These results showed that the method is sensitive and reliable for simultaneous determination of six metabolites, which might indicate potential risk factors for NTDs, aid early diagnosis and provide more insights into the pathogenesis of NTDs.

Waitlist priority for hepatocellular carcinoma beyond milan criteria: a potentially appropriate decision without a structured approach

Due to the risk of waitlist dropout from tumor progression, liver transplant candidates with hepatocellular carcinoma (HCC) within Milan criteria (MC) receive standardized exception points. An expansion of this process to candidates with HCC beyond MC has been proposed, though it remains controversial. This study sought to better define the utilization of exception points in candidates with HCC beyond MC and the associated outcomes. We reviewed all nonstandardized HCC applications that underwent formal regional review board evaluation between January 1, 2005 and March 2, 2011; 2184 initial HCC exception point applications were submitted. Of these, 41.9% fulfilled MC, 26.6% fulfilled University of California-San Francisco (UCSF) criteria and 17.6% exceeded UCSF criteria. The majority of applications were accepted: 89.8% within UCSF and 71.2% beyond UCSF. There was a significantly (p < 0.001) higher risk of death on the waitlist or within 90 days of waitlist removal for candidates within UCSF (12.4%) or beyond UCSF (13.0%) criteria, compared to candidates with HCC within MC (6.0%). However, posttransplant outcomes were similar. While these results suggest increasing access to candidates with HCC beyond MC, comprehensive documentation of tumor characteristics and of successful downstaging is needed to ensure priority is restricted to those with the highest likelihood of favorable posttransplant outcome.

Association between PKA gene polymorphism and NTDs in high risk Chinese population in Shanxi

OBJECTIVE

This study aimed to investigate the single nucleotide polymorphisms (SNPs) of PKA and neural tube defects (NTDs) in Chinese population.

METHOD

A total of 183 NTDs cases and 200 healthy controls were used in this study. 7 selected single nucleotide polymorphism (SNP) sites in the PKA gene were analyzed with MassArray high-throughput DNA analyzer with matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. A series of statistical methods were carried out to investigate the correlation between the SNPs and the patient susceptibility to NTDs.

RESULTS

Statistical analysis showed a significant correlation between the SNP sites rs12132032 in PRKACB and NTDs. The AA genotype, A-allele and dominant AA in rs12132032 significantly increased the incidence of NTDs especially anencephaly (OR=3.87, 95% CI: 1.80-8.34 with genotype; OR=2.08, 95% CI: 1.43-3.04 with allele; OR=3.10, 95% CI: 1.53-6.26 with dominant). The T-allele of rs594631 in PRKACB was correlative with NTDs in male but not in female.

CONCLUSIONS

The gene polymorphism loci rs12132032 in PRKACB maybe a potential risk factor for anencephaly in Chinese population from Shanxi, while gender susceptibility may influence the correlation.

Association of SMO polymorphisms and neural tube defects in the Chinese population from Shanxi Province

OBJECTIVE

This study aimed to investigate the single nucleotide polymorphisms (SNPs) of SMO and neural tube defects (NTDs) in Chinese population.

METHOD

A total of 113 NTDs cases and 138 healthy controls were used in this study. 10 selected single nucleotide polymorphism (SNP) sites in the SMO gene were analyzed with MassArray high-throughput DNA analyzer with matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. A series of statistical methods were carried out to investigate the correlation between the SNPs and the patient susceptibility to NTDs.

RESULTS

The C allele of rs3824 increased the risk of spina bifida (OR=2.52; 95% CI: 1.18, 5.38; p=0.026) but not the risk of anencephaly or encephalocele. Significant differences were found between spina bifida and controls when we compared the GG group with the CC+CG group (OR=2.66; 95% CI: 1.26, 5.61; p=0.011). CC+CG genotype was a risk factor for spina bifida.

CONCLUSIONS

The gene polymorphism loci rs3824 of SMO was closely related to spina bifida in Chinese population from Shanxi. The haplotype GA in rs3824 and rs9706 increased the risk of NTDs particularly spina bifida in women.

Minimal alveolar concentration of sevoflurane for induction of isoelectric electroencephalogram in middle-aged adults

BACKGROUND

We determined the minimal alveolar concentration (MAC) of sevoflurane inducing an isoelectric EEG in 50% of adult subjects (MACie).

METHODS

We included 31 middle-aged subjects; 30 subjects finished the study protocol and received sevoflurane at preselected concentrations according to a modified Dixon 'up-and-down' design starting at 1.7 vol% with 0.2 vol% steps size. General anaesthesia was induced and maintained with sevoflurane; tracheal intubation was facilitated with cisatracurium. After a period of 30 min before skin incision, the state of isoelectric EEG was considered as significant when a burst suppression ratio of 100% lasted for >1 min. The haemodynamic responses to skin incision and the vasopressor requirement to maintain stable haemodynamic status were also analysed according to the EEG state.

RESULTS

MACie was 3.5% (95% confidence interval, 3.4-3.7%) in middle-aged subjects. When compared with subjects not in isoelectric EEG state, subjects in isoelectric EEG state received more phenylephrine to maintain stable haemodynamics (10 of 10 compared with 7 of 20 subjects, P=0.001) and experienced less sympathetic responses to skin incision (1 of 10 compared with 11 of 20 subjects, P=0.024).

CONCLUSIONS

MACie for sevoflurane was ∼2.1 times MAC for immobilization in phenobarbital premedicated middle-aged adults. Sevoflurane-induced isoelectric EEG state is associated with significant cardiovascular depression but reduced haemodynamic responses to skin incision.

Effects of Storage Solutions on the Viability of Human Umbilical Cord Mesenchymal Stem Cells for Transplantation

Human umbilical cord-derived mesenchymal stem cell (UC-MSC) transplantation has shown promise for the treatment of various diseases. For clinical applications, UC-MSCs have been stored in 0.9% saline, 5% dextrose, dextrose and sodium chloride injection, Plasma-Lyte A, 1% human serum albumin (1% HSA), or 5% HSA before administration, but the effect of storage conditions on the viability and biological function of the cells remains unknown. Freshly harvested UC-MSCs were resuspended and incubated in these solutions for 2, 4, or 6 h at 4°C or room temperature (24°C). Cell viability, apoptotic/necrotic fraction, poststorage growth potential, immunophenotype, immunosuppressive capacity, and differentiation capacity were analyzed. When stored in parenteral solutions, UC-MSCs showed progressive deterioration in survival viability and adhesion ability. After 6-h storage, the best viability and attachment rate of UC-MSCs decreased to 83.0 ± 1.6% and 71.8 ± 3.2%, respectively. Our results suggested that UC-MSCs in these conditions lose their viability in a short time. However, it seems that the other biological functions of the surviving UC-MSCs were little affected. Since UC-MSCs suspended in these mediums lose their survival viability in a short time to levels significantly below the permissible limits (70%) by FDA, precautions need to be taken on using these solutions as suspension medium and further studies on the optimal methods for preservation are urgent.

Clonal diversity of recurrently mutated genes in myelodysplastic syndromes

Recent studies suggest that most cases of myelodysplastic syndrome (MDS) are clonally heterogeneous, with a founding clone and multiple subclones. It is not known whether specific gene mutations typically occur in founding clones or subclones. We screened a panel of 94 candidate genes in a cohort of 157 patients with MDS or secondary acute myeloid leukemia (sAML). This included 150 cases with samples obtained at MDS diagnosis and 15 cases with samples obtained at sAML transformation (8 were also analyzed at the MDS stage). We performed whole-genome sequencing (WGS) to define the clonal architecture in eight sAML genomes and identified the range of variant allele frequencies (VAFs) for founding clone mutations. At least one mutation or cytogenetic abnormality was detected in 83% of the 150 MDS patients and 17 genes were significantly mutated (false discovery rate ≤0.05). Individual genes and patient samples displayed a wide range of VAFs for recurrently mutated genes, indicating that no single gene is exclusively mutated in the founding clone. The VAFs of recurrently mutated genes did not fully recapitulate the clonal architecture defined by WGS, suggesting that comprehensive sequencing may be required to accurately assess the clonal status of recurrently mutated genes in MDS.

Histone modification mapping in human brain reveals aberrant expression of histone H3 lysine 79 dimethylation in neural tube defects

Neural tube defects (NTDs) are severe, common birth defects that result from failure of neural tube closure, but their pathological mechanisms are not yet fully understood. Histone modifications have an important role in gene regulation during fetal development. We therefore hypothesized that the human NTDs may be partly caused by an imbalance in metabolism, perhaps caused by nutritional deficiencies, that leads to aberrant histone modifications. Here, we report a screen of fetal brain histone modifications using 2D nano-LC strong cation exchange reverse phase (SCX/RP) MS/MS and the identification of 61 unique post-translational modification sites on histones H1, H2a, H2b, H3, and H4. Of these, 38 sites are novel (not already found in the Uniprot database). Furthermore, we compared the histone modification patterns between normal brains and NTD brains special of which maternal folate levels were lower than of normal control. The results showed that histone H3 lysine 79 dimethylation (H3K79me2) and a novel identified site, H2bK5 monomethylation (H2bK5me1), were completely absent in individuals with NTDs. Follow-up Western blotting validated the decreased H3K79me2 expression in brains with NTDs, but the amplified samples experiments displayed that decreased H3K79me2 expression was not suitable for all samples with NTDs. Furthermore, folate-free treated mouse embryonic stem cells induced the decreased H3K79me2 level. Subsequently, our ChIP results in normal fetal brain tissues showed that H3K79me2 binds to SUFU, RARA and ITGA3 which induce NTDs phenotype after knockout in mice, and in NTDs brain tissues the bindings of H3K79me2 to these three genes were significantly altered. Taken together, our study indicated that low folate treatment might attenuate H3K79 dimethylation, further affect its regulate activation on target genes, some of which are NTDs-resulting associated, lastly interrupt early embryo developing. Our study increases the understanding of normal fetal brain histone modifications and provides a platform for investigating histone modifications in neural disease and also has an insight into a potential role of aberrant histone modification in etiology of NTDs.

Detection of copy number variants reveals association of cilia genes with neural tube defects

Background

Neural tube defects (NTDs) are one of the most common birth defects caused by a combination of genetic and environmental factors. Currently, little is known about the genetic basis of NTDs although up to 70% of human NTDs were reported to be attributed to genetic factors. Here we performed genome-wide copy number variants (CNVs) detection in a cohort of Chinese NTD patients in order to exam the potential role of CNVs in the pathogenesis of NTDs.

Methods

The genomic DNA from eighty-five NTD cases and seventy-five matched normal controls were subjected for whole genome CNVs analysis. Non-DGV (the Database of Genomic Variants) CNVs from each group were further analyzed for their associations with NTDs. Gene content in non-DGV CNVs as well as participating pathways were examined.

Results

Fifty-five and twenty-six non-DGV CNVs were detected in cases and controls respectively. Among them, forty and nineteen CNVs involve genes (genic CNV). Significantly more non-DGV CNVs and non-DGV genic CNVs were detected in NTD patients than in control (41.2% vs. 25.3%, p<0.05 and 37.6% vs. 20%, p<0.05). Non-DGV genic CNVs are associated with a 2.65-fold increased risk for NTDs (95% CI: 1.24–5.87). Interestingly, there are 41 cilia genes involved in non-DGV CNVs from NTD patients which is significantly enriched in cases compared with that in controls (24.7% vs. 9.3%, p<0.05), corresponding with a 3.19-fold increased risk for NTDs (95% CI: 1.27–8.01). Pathway analyses further suggested that two ciliogenesis pathways, tight junction and protein kinase A signaling, are top canonical pathways implicated in NTD-specific CNVs, and these two novel pathways interact with known NTD pathways.

Conclusions

Evidence from the genome-wide CNV study suggests that genic CNVs, particularly ciliogenic CNVs are associated with NTDs and two ciliogenesis pathways, tight junction and protein kinase A signaling, are potential pathways involved in NTD pathogenesis.

Silencing of triggering receptor expressed on myeloid cells-2 enhances the inflammatory responses of alveolar macrophages to lipopolysaccharide

Triggering receptor expressed on myeloid cells-2 (TREM-2) has been shown to attenuate inflammatory responses in various cell lines including bone marrow-derived macrophages, hepatic macrophages, osteoclasts and dendritic cells. However, its effects on alveolar macrophages remain unknown. Lentivirus-mediated RNA interference (RNAi) is a post-transcriptional gene silencing method, which is capable of degrading target genes specifically and efficiently. In this study, we silenced TREM-2 in murine alveolar macrophages by using lentivirus-mediated short hairpin RNA (shRNA) and evaluated the effects of TREM-2 silencing on expression of toll-like receptor-4 (TLR-4), tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) in response to lipopolysaccharide (LPS). Alveolar macrophages were transfected with shRNA targeting TREM-2 by use of lentivirus vector, non-sense shRNA as a negative control or empty lentivirus vector as a blank control. Silencing of TREM-2 was assessed by real‑time fluorescence quantitative PCR and flow cytometry. Following LPS stimulation, the levels of TLR-4, TNF-α and IL-10 expressed in alveolar macrophages were measured by real-time PCR, flow cytometry or ELISA. TREM-2 expression on alveolar macrophages was downregulated significantly by lentivirus-mediated shRNA treatment at the transcriptional and translational levels. However, alveolar macrophages that received non-sense shRNA or empty lentivirus vectors showed no effects on TREM-2 expression. Silencing of TREM-2 enhanced expression of TLR-4, as well as TNF-α and IL-10, by alveolar macrophages following LPS stimulation. These results indicate a significant effect of TREM-2 on attenuating the LPS-induced inflammatory response of murine alveolar macrophages, which may be dependent on TLR-4.

Association of β-catenin with P-Smad3 but not LEF-1 dissociates in vitro profibrotic from anti-inflammatory effects of TGF-β1

Transforming growth factor β1 (TGF-β1) is known to be both anti-inflammatory and profibrotic. Cross-talk between TGF-β/Smad and Wnt/β-catenin pathways in epithelial-mesenchymal transition (EMT) suggests a specific role for β-catenin in profibrotic effects of TGF-β1. However, no such mechanistic role has been demonstrated for β-catenin in the anti-inflammatory effects of TGF-β1. In the present study, we explored the role of β-catenin in the profibrotic and anti-inflammatory effects of TGF-β1 by using a cytosolic, but not membrane, β-catenin knockdown chimera (F-TrCP-Ecad) and the β-catenin/CBP inhibitor ICG-001. TGF-β1 induced nuclear Smad3/β-catenin complex, but not β-catenin/LEF-1 complex or TOP-flash activity, during EMT of C1.1 (renal tubular epithelial) cells. F-TrCP-Ecad selectively degraded TGF-β1-induced cytoplasmic β-catenin and blocked EMT of C1.1 cells. Both F-TrCP-Ecad and ICG-001 blocked TGF-β1-induced Smad3/β-catenin and Smad reporter activity in C1.1 cells, suggesting that TGF-β1-induced EMT depends on β-catenin binding to Smad3, but not LEF-1 downstream of Smad3, through canonical Wnt. In contrast, in J774 macrophages, the β-catenin level was low and was not changed by interferon-γ (IFN-γ) or lipopolysaccharide (LPS) with or without TGF-β1. TGF-β1 inhibition of LPS-induced TNF-α and IFN-γ-stimulated inducible NO synthase (iNOS) expression was not affected by F-TrCP-Ecad, ICG-001 or by overexpression of wild-type β-catenin in J774 cells. Inhibition of β-catenin by either F-TrCP-Ecad or ICG-001 abolished LiCl-induced TOP-flash, but not TGF-β1-induced Smad reporter, activity in J774 cells. These results demonstrate for the first time that β-catenin is required as a co-factor of Smad in TGF-β1-induced EMT of C1.1 epithelial cells, but not in TGF-β1 inhibition of macrophage activation. Targeting β-catenin may dissociate the TGF-β1 profibrotic and anti-inflammatory effects.

The maternal folate hydrolase gene polymorphism is associated with neural tube defects in a high-risk Chinese population

Folate hydrolase 1 (FOLH1) gene encodes intestinal folate hydrolase, which regulates intestinal absorption of dietary folate. Previous studies on the association between polymorphisms rs202676 and rs61886492 and the risk of neural tube defects (NTDs) were inconclusive. A case-control study of women with NTD-affected pregnancies (n = 160) and controls (n = 320) was conducted in the Chinese population of Lvliang, a high-risk area for NTDs. We genotyped the polymorphic sites rs202676 and rs61886492 and assessed maternal plasma folate and total homocysteine (tHcy). Our results showed that in case group, plasma folate concentrations were 18 % lower compared with those of control group (8.32 vs. 6.79 nmol/L, p = 0.033) and tHcy concentrations were 17 % higher (10.47 vs. 12.65 μmol/L, p = 0.047). Almost all samples had the rs61886492 GG genotype (99.78 %). The result showed that the frequency of GG genotype in rs202676 was significantly higher in group with multiple NTDs than in controls (p = 0.030, OR = 2.157, 95 % CI, 1.06-4.38). The multiple-NTD group showed higher maternal plasma concentrations of tHcy (10.47 vs. 13.96 μmol/L, p = 0.024). The GG genotype of rs202676 had a lower maternal folate and higher tHcy concentrations than other genotypes with no significant differences. The result of structural prediction indicated that this variation might change the spatial structure of the protein. These results suggested that the maternal polymorphism rs202676 was a potential risk factor for multiple NTDs in this Chinese population. The allele G might affect maternal plasma folate and tHcy concentration.

Nucleofection of a DNA vaccine into human monocyte-derived dendritic cells

An efficient method for delivering DNA vaccines into dendritic cells is considered to be of paramount importance. Electroporation-based technology (nucleofection) has gained increasingly popularity, but few reports focused on the possible functional consequences related to this method. In this study, the nucleofection technique was used to transfer the recombinant plasmid into hMoDCs for phenotype expression analysis and immunopotency detection. The results showed that the nucleofection of increasing concentrations of plasmid DNA decreased the viability of the hMoDCs. The welfare of nucleofected hMoDCs depended on the dosage of the plasmid and the plasmid's retention time within the cells. Accompanied by the process of nucleofection, it would bring some non-specific changes. The methodology reported here is suggestive of a feasible system for DNA vaccine transfer into hMoDCs with the caution of certain undesired effect.

Maternal PCMT1 gene polymorphisms and the risk of neural tube defects in a Chinese population of Lvliang high-risk area

Protein-L-isoaspartate (D-aspartate) O-methyltransferase 1 (PCMT1) gene encodes for the protein repair enzyme L-isoaspartate (D-aspartate) O-methyltransferase (PIMT), which is known to protect certain neural cells from Bax-induced apoptosis. Previous study has shown that PCMT1 polymorphisms rs4552 and rs4816 of infant are associated with spina bifida in the Californian population. The association between maternal polymorphism and neural tube defects is still uncovered. A case-control study was conducted to investigate a possible association between maternal PCMT1 and NTDs in Lvliang high-risk area of Shanxi Province in China, using a high-resolution DNA melting analysis genotyping method. We found that increased risk for anencephaly in isolated NTDs compared with the normal control group was observed for the G (vs. A) allele (p=0.034, OR=1.896, 95% CI, 1.04-3.45) and genotypes GG+GA (p=0.025, OR=2.237, 95% CI, 1.09-4.57). Although the significance was lost after multiple comparison correction, the results implied that maternal polymorphisms in PCMT1 might be a potential genetic risk factor for isolated anencephaly in this Chinese population.

Overexpression of Aurora-A enhances invasion and matrix metalloproteinase-2 expression in esophageal squamous cell carcinoma cells

Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive cancers, and metastasis is the principal cause of death in ESCC patients. It has been shown that amplification and overexpression of mitotic serine/threonine kinase Aurora-A occur in several types of human tumors, including ESCC. Moreover, increase in expression levels of Aurora-A has been predicted to correlate with the grades of tumor differentiation and invasive capability. However, the mechanisms by which Aurora-A mediates its invasive effects still remain elusive. In this article, we showed that Aurora-A overexpression significantly increased cell migration and invasion as well as secretion and expression of matrix metalloproteinase-2 (MMP-2). Conversely, siRNA-mediated knockdown of Aurora-A expression in human ESCC cells led to inhibition of cell invasiveness as well as secretion and expression of MMP-2. In addition, Aurora-A overexpression increased phosphorylation levels of p38 mitogen-activated protein kinase (MAPK) and Akt, and the knockdown of Aurora-A by siRNA decreased the activity of p38 MAPK and Akt. Moreover, the blocking of the activity of above kinases using chemical inhibitors suppressed the ability of Aurora-A to induce MMP-2 secretion and expression as well as cell invasion. These data show that overexpression of Aurora-A contributes to the malignancy development of ESCC by enhancing tumor cell invasion as well as MMP-2 activity and expression, which can occur through signaling pathways involving p38 MAPK and Akt protein kinases. Taken together, these studies provide a molecular basis for promoting the role of Aurora-A in malignancy development of ESCC.

Glutamate carboxypeptidase II gene polymorphisms and neural tube defects in a high-risk Chinese population

Glutamate carboxypeptidase II (GCPII) catalyzes the hydrolysis of N-acetylaspartylglutamate into N-acetylaspartate and glutamate in the brain. Animal experiments suggested that GCPII plays an essential role in early embryonic development. Previous studies provided conflicting results on the effect of the GCPII rs61886492 C>T (or 1561C>T) polymorphism on NTDs. In the Lvliang area of Shanxi province, where the incidence of NTDs is the highest in China, a case-control study was conducted to investigate possible association between the GCPII rs61886492 and rs202676 polymorphisms and NTD risk. Results indicated all the case and control samples displayed the rs61886492 GG genotype. Although no significant differences in rs202676 genotype or allele frequencies were found between the NTD and control groups, the combined AG+GG genotype group was significantly associated with anencephaly (p = 0.03, OR = 2.11, 95% CI, 1.11-4.01), but not with spina bifida or encephalocele. Overall, the rs202676 A>G polymorphism is a potential risk factor for anencephaly. The results of this study suggest that phenotypic heterogeneity may exist among NTDs in this Chinese population.

Endotoxin tolerance attenuates liver ischemia/reperfusion injury by down-regulation of interleukin-1 receptor-associated kinase 4 in kupffer cells

AIM

The aim of this study was to study the role of interleukin-1 receptor-associated kinase 4 (IRAK-4) in the formation of endotoxin tolerance (ET) in liver ischemia/reperfusion (I/R) injury.

METHODS

Animals were randomly divided into 3 groups: control group, I/R group, and ET group. Liver morphological changes were observed using optical microscopy with hematoxylin eosin (HE) staining. Alanine aminotransferase (ALT) was quantified to measure liver functional injury. The messenger RNA (mRNA) and protein expressions of IRAK-4 in Kupffer cells (KCs) isolated from recipients were detected using real-time polymerase chain reaction (PCR) and Western blot, respectively. The activities of NF-κB and the supernatant levels of tumor necrosis factor-alpha (TNF-α), IL-10 were assayed using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Endotoxin preconditioning improved hepatic tissue injury as indicated by morphological analysis, whereas serum ALT levels were significantly decreased at various times (P < .05); concurrently, the expression of IRAK-4 and TNF-α in KCs was down-regulated (P < .05) and the secretion of IL-10 was enhanced (P < .05); NF-κB DNA-binding activity of KCs was also significantly inhibited by endotoxin preconditioning (P < .05).

CONCLUSION

Endotoxin preconditioning attenuated the liver I/R injury caused by transplantation. The expression of IRAK-4 in KCs may play an important role in the formation of ET.

Intravenous umbilical cord mesenchymal stem cell infusion for the treatment of combined malnutrition nonunion of the humerus and radial nerve injury

Nonunion and nerve injury are the most severe and common complications of bone fracture treatments. There is still no ideal therapy for these two complications. In this report, we first applied umbilical cord mesenchymal stem cell (UC-MSC) therapy to one patient with both nonunion and nerve injury, and observed the therapeutic effects. UC-MSCs were produced and expanded according to a clinical-grade technique using serum-free medium enriched in human platelet lysate. Flow cytometry was performed to evaluate the purity of UC-MSCs, which were then intravenously injected. At 60 days postinjection, clinical examinations were performed to evaluate the therapeutic effects. Compared with before treatment, the patient’s nerve reflex was present, and their muscle tone and strength increased, and x-ray and electromyography analysis further showed that the fracture gap disappeared and the nerve conduction velocity increased with shorter latency and higher amplitude. Furthermore, the clinical evolution was favorable and no side effects were observed during the 1-year follow-up. Overall, this novel treatment might open up a new strategy for the treatment of bone fracture complications.

[Pretreatment methods of urine proteomics in children with primary nephrotic syndrome]

OBJECTIVE

To optimize a pretreatment method of urine proteomics in children with primary nephrotic syndrome.

METHODS

Urine from children with primary nephrotic syndrome was treated in different pH and isolated by cold acetone precipitation for different durations. Then the amounts and kinds of proteins were compared by quantify, SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional electrophoresis (2-DE) in order to optimize a way to deal with urine protein.

RESULTS

Most proteins were obtained at pH 2.7. The amounts of protein precipitated by acetone for 0.5 hr was obviously less than those precipitated for 1 and 2 hrs (P<0.05), while there was no significant difference between the amount of protein precipitated for 1 and for 2 hrs. Protein precipitated by cold acetone for 1 hr at pH 2.7 was selected as the best pretreatment method. Satisfactory 2-DE maps can be acquired.

CONCLUSIONS

Urine protein can be best obtained at pH 2.7 and precipitated by cold acetone for 1 hr.

Association between a 45-bp 3'untranslated insertion/deletion polymorphism in exon 8 of UCP2 gene and neural tube defects in a high-risk area of China

Uncoupling protein 2(UCP2) is an attractive candidate gene for screening neural tube defects (NTDs) risk. In this study, polymerase chain reaction and agarose gel electrophoresis were used to determine the distribution of the polymorphism in a case group of 140 deliveries with NTDs, and a control group of 251 normal newborns. We found that the frequencies of allele I and genotypes ID + II were higher in the case group than in the control group (P = .167, OR = 1.4, 95% CI, 0.9-2.1; P = .132, OR = 1.44, 95% CI, 0.89-2.33, respectively); and at low maternal educational level, the frequency of ID + II genotypes was significantly higher in the NTD case group (P < .05, OR = 1.7, 95% CI, 1.01-2.79). The result suggested that the polymorphism in UCP2 may be a potential genetic risk factor for NTDs in a high-risk area of China, and the association was influenced by maternal education.

Inhibition of allergic airway inflammation by antisense-induced blockade of STAT6 expression

BACKGROUND

The signal transducer and activator of transcription 6 (STAT6) expression in lung epithelial cells plays a pivotal role in asthma pathogenesis. Activation of STAT6 expression results in T helper cell type 2 (Th2) cell differentiation leading to Th2-mediated IgE production, development of allergic airway inflammation and hyperreactivity. Therefore, antagonizing the expression and/or the function of STAT6 could be used as a mode of therapy for allergic airway inflammation.

METHODS

In this study, we synthesized a 20-mer phosphorothioate antisense oligonucleotide (ASODN) overlapping the translation starting site of STAT6 and constructed STAT6 antisense RNA (pANTI-STAT6), then transfected them into murine spleen lymphocytes and analyzed the effects of antagonizing STAT6 function in vitro and in a murine model of asthma.

RESULTS

In vitro, we showed suppression of STAT6 expression and interleukin (IL)-4 production of lymphocytes by STAT6 ASODN. This effect was more prominent when cells were cultured with pANTI-STAT6. In a murine model of asthma associated with allergic pulmonary inflammation in ovalbumin (OVA)-sensitized mice, local intranasal administration of fluorescein isothiocyanate (FITC)-labeled STAT6 ASODN to DNA uptake in lung cells was accompanied by a reduction of intracellular STAT6 expression. Such intrapulmonary blockade of STAT6 expression abrogated signs of lung inflammation, infiltration of eosinophils and Th2 cytokine production.

CONCLUSION

These data suggest a critical role of STAT6 in the pathogenesis of asthma and the use of local delivery of STAT6 ASODN as a novel approach for the treatment of allergic airway inflammation such as in asthma.

[Study on antineoplastic effect of earthworm coelomic fluid in vitro]

OBJECTIVE

To explore the antineoplastic effect in vitro of earthworm coelomic fluid (ECF)on growth inhibition and its mechanism for the tumor cell lines Siha, SW480, Colo205 and PC12.

METHODS

MTT colorimetric assay, flow cytometry and morphological analysis were used to test its antitumor activity on tumor cell lines and normal cell line Cos7 in vitro.

RESULTS

ECF can inhibit the cell growth of Siha, SW480, Colo205, PC12 and Cos7. But different tumor cell lines showed different sensitivity.

CONCLUSION

EFC can significantly inhibit the proliferation of tumor cells in vitro by inducing tumor cells apoptosis.

[Experimental research on anti-respiratory syncytial virus effect in vitro of earthworm coelomic fluid]

OBJECTIVE

To explore the antivirus function in vitro of earthworm coelomic fluid (ECF) by researching its effect on inhibiting respiratory syncytial virus (RSV).

METHODS

By the method of Hep-2 cell culture and using ribavirin as a positive control, the anti-RSV effect of ECF was investigated by observing cytopathic effect (CPE) with MTT colorimetric assay.

RESULTS

In Hep-2 cells, the CC50 of ECF and ribavirin were 3.11 mg/ml and 1.35 mg/ml separately. In the experiment of ECF directly killing RSV, the IC50 of ECF was 184.1 microg/ml, SI was 16.87; In the experiment of ECF preventing RSV invasion, no antiviral function of ECF within the experimental concentration range was observed; In the experiment of ECF inhibiting RSV replication, the IC50 of ECF was 1555. 8 microg/ml, SI was 1.99.

CONCLUSION

ECF couldn't prevent virus from invading into host cell, but showed direct killing-virus function and inhibition of the virus replication.

Hepatocyte gene transfer mediated by stable polyplexes based on MPP-containing DNA complexes

BACKGROUND

In the field of gene therapy, viral vectors as delivery tools have a number of disadvantages for medical application. This study aimed to explore a novel nonviral vector as a vehicle for gene therapy.

METHODS

Transvector-rpE-MPP and EGFP (enhanced green fluorescent protein) were used as the gene transfer carrier and the reporter gene, respectively. Polyplexes which integrate transvector-rpE-MPP, the object gene, and EGFP were formed. The optimal charge ratio, stability, and transduction capacity of the polyplexes in mouse hepatocytes in vitro and in mouse liver in vivo were investigated. The polyplexes of transvector-rpE-MPP and pcDNA(3)-EGFP, with charge ratios of 0, 0.25, 0.5, 0.75, 1 and 1.5 were compared to determine the optimal charge ratio.

RESULTS

Polyplexes with charge ratios of 1:1 were most stable; pcDNA(3)-EGFP in these complexes resisted digestion by DNase I and blood plasma. On the other hand, pcDNA(3)-EGFP alone was digested. Fluorescence analysis indicated that transvector-rpE-MPP successfully delivered the reporter gene EGFP into hepatocytes and that EGFP expression was detected in hepatocyte cultures and in liver tissue.

CONCLUSION

These results have laid a foundation for further study of a novel nonviral gene delivery system.

All-trans-retinoic acid alters Smads expression in embryonic neural tissue of mice

Retinoic acid can cause malformations of the developing nervous system. Smad signaling is involved in embryonic development. The current study investigated all-trans-retinoic acid (ATRA)-induced alteration of Smad expression in the developing neural tubes of mice. Pregnant mice were treated with a single dose of 50 mg/kg ATRA by oral gavage on embryonic day E7. Western immunoblotting was used to examine Smads proteins, particularly phosphorylated (p-) Smad1, total Smad1 and Smad6 in the neural tissue of the embryos on E8-E11 following treatment. Results showed that ATRA treatment significantly increased expression of both p-Smad1 and total Smad1, while Smad6 was decreased in neural tissues of ATRA-exposed embryos in utero from E8 to E11, a critical period for neural tube formation. Data suggest that disruption of Smad signaling may be involved in ATRA-induced neural tube defects.

Dendritic cells and chronic hepatitis B

The immune function disorders in patients with chronic hepatitis B (CHB) lead to persistent damage of their liver cells and have impact on the ability to clear the virus. Dendritic cells (DCs) are the most important antigen-presenting cells in body. They help to generate sufficient immune response by the invasion of pathogens. The quantity and functionality of DCs directly correlate with the normal function of the host's immune response. Not only can DCs be resistant to the virus, but also serve as vehicles for the virus to spread and escape immune injury. Therefore the research on DCs and improving their function under the state of CHB is quite significant.

Calmodulin kinase II activation of mitogen-activated protein kinase in PC12 cell following all-trans retinoic acid treatment

Previous studies have shown that apoptosis can be mediated by activation of either calmodulin kinase II (CaMKII) or mitogen-activated protein kinase (MAPK), ERK and p38. In the present study, we investigated whether CaMKII is involved in activation of ERK and p38 in response to all-trans retinoic acid (ATRA) treatment in PC12 cells. Results showed that ATRA-induced activation of ERK and p38 occurred later than that of CAMKII. Knockdown of CAMKII by siRNA significantly suppressed ATRA-induced activation of ERK and p38. These results demonstrated that activation of ERK and p38 following ATRA exposure is CAMKII-dependent. Treatment with ATRA also resulted in cell death characterized by apoptosis in PC12 cells. Results suggest that CaMKII-dependent activation of ERK and p38 is related to apoptotic cell death.

[Optimization of human anti-HBsAg scFv secretary expression in Escherichia coli]

OBJECTIVE

To explore the conditions for high expression of anti-HBsAg scFv A-15 in E. coli, increase the production of the scFv in the culture medium.

METHODS

By changing induction occasion, concentration of inductor IPTG and induction time, influence of various conditions on expression of anti-HBsAg scFv A-15 was analyzed through ELISA. In addition, the effects of sucrose, glycine and Triton X-100 at different concentrations on the scFv excretion into culture medium was evaluation.

RESULTS

The optimal expression conditions were as follows: the induction was started after culturing for 4 h, the concentration of IPTG was 0.5 mmol/L, and the induction lasted for 8 h. The scFv affinity in culture medium with 0.3 mol/L sucrose, 2% glycine, 1% Triton X-100, 16.78-fold higher, respectively than that without the three chemicals. The final yield of anti-HBsAg scFv A-15 was estimated to be 7.4 mg/L.

CONCLUSION

The conditions for production of anti-HBsAg scFv A-15 were optimized, which provides a practical method for more efficient production of the scFv in E. coli for further studying structure and function.

Purification and characterization of deoxyribonuclease from earthworm Eisenia foetida

OBJECTIVE

To purify a kind of deoxyribonuclease from earthworm Eisenia foetida (named earthworm DNase, EDNase) and study its characteristics.

METHODS

Acetone precipitation, ion-exchange chromatography, high performance liquid chromatography, SDS-PAGE, Capillary electrophoresis isoelectric focusing and MALDI-TOP MS were used for the study.

RESULTS

This purified protocol improved 137-fold purification and 45.6% recovery of enzyme activity. The molecular mass of EDNase was estimated to be 63,000. Mg2+, Mn2+ and Ca2+ were strong inhibitors of EDNase, while Na+ slightly increased the enzyme activity. The enzyme was completely stable in the pH range from 4.4 to 5.2 and had a pH optimum of 4.8. The optimum temperature was 37 degree C and the enzyme was stable up to 40 degree C. The pI of the enzyme was 6.20. Km and Vmax for the enzyme were 1.52 g/L and 4.89 mg/(mL.min), respectively, with calf thymus DNA as substrate. The enzyme was able to degrade chromosomal DNA, linear lambda-bacteriophage DNA as well as supercoiled plasmid DNA, but didn't display any RNase activity.

CONCLUSION

This kind of deoxyribonuclease possesses unique characteristics, which is different from the deoxyribonucleases which we have known before.

Correlation of polymorphism of MTHFRs and RFC-1 genes with neural tube defects in China

BACKGROUND

Maternal periconceptional supplementation of folate reduces the incidence of neonatal Neural Tube Defects, indicating that changes in folate metabolism play a role in formation of NTDs. The mutations on two genes involved in folate metabolism, the C677 of the MTHFR gene and the RFC-1(A80G) gene are potential risk factors of NTDs.

METHODS

In this study, we analyzed the genotypic distributions and allele frequencies of MTHFR C677T and RFC-1 A80G polymorphisms in DNA samples from mothers with at least one previous child with NTDs (the NTD group) and controls.

RESULTS

Our results indicated that there was a significant difference in the genotype and allele frequencies of RFC-1 80A-->G between the NTD group and controls (p = .008 and p = .017, respectively). There was, however, no significant difference in the genotype and allele frequencies of the MTHFR 677C-->T polymorphism between the NTD group and controls. The NTD group was further separated into the upper and lower types by location of abnormalities. The frequency of RFC-1 80A/G and 80G/G was significantly higher in the upper group than the control (p = .009 and p = .005, respectively). The frequency of G-alleles was also significantly higher in the upper group than the control (OR 2.42; p = .006; 95% CI: 1.28-4.58). For the MTHFR C677 gene, the frequency of T-alleles was significantly lower in the lower defect type than the control group (OR 0.32; p = .027; 95% CI: 0.11-0.9).

CONCLUSIONS

These results suggest that in the Shanxi population RFC-1 polymorphisms may play a role in NTD risk, whereas the impact of MTHFR C677T polymorphisms requires further clarification. Birth Defects Research (Part A) 2008.

[Co-expression of HSV-1 gD gene and interleukin-2 gene in dendritic cell]

OBJECTIVE

To construct eukaryotic expression plasmid IRES-gD-IL-2 which contains both HSV-1 glycoprotein D (gD) gene and IL-2 gene and to induce it to express in antigen presenting cell (APC) -- dendritic cells (DCs).

METHODS

The whole sequence of gD and IL-2 were amplified by PCR assay. After confirmation by PCR, double-enzyme digestion and sequencing, these genes were directly cloned into eukaryotic expression vector IRES, then were transfected into DCs. Western blotting was employed to identify the transcription and expression of gD gene.

RESULTS

The results of PCR and enzyme digestion showed that the recombinant expression plasmid contained correct fragments, and the transcription and expression of gD were confirmed by Western blotting.

CONCLUSION

The recombinant expression vector IRES-gD-IL-2 was constructed, the results of the Western blotting showed that the recombinant protein could be identified by gD- specific antibody, therefore the protein has immunologic competence.

Screening and evaluation of human single-chain fragment variable antibody against hepatitis B virus surface antigen

BACKGROUND

Phage display technology has become a vital tool in studies aimed at identifying molecules binding to a specific target. It enables the rapid generation and selection of high affinity, fully human antibody product candidates to essentially any disease target appropriate for antibody therapy. In this study, we prepared the recombinant single-chain fragment variable (ScFv) antibody to hepatitis B virus surface antigen (HBsAg) by the phage display technology for obtaining a virus-targeting mediator.

METHODS

mRNA was isolated from B-lymphocytes from a healthy volunteer and converted into cDNA. The fragment variables of heavy and light chain were amplified separately and assembled into ScFv DNA with a specially constructed DNA linker by polymerase chain reaction. The ScFv DNA was ligated into the phagmid vector pCANTAB5E and the ligated sample was transformed into competent E.coli TG1. The transformed cells were infected with M13K07 helper phage to form a human recombinant phage antibody library. The volume and recombinant rate of the library were evaluated by bacterial colony count and restriction analysis. After two rounds of panning with HBsAg, the phage clones displaying ScFv of the antibody were selected by enzyme-linked immunosorbant assay (ELISA) from the enriched phage clones. The antigen binding affinity of the positive clone was detected by competition ELISA. HB2151 E.coli was transfected with the positive phage clone demonstrated by competition ELISA for production of a soluble form of the anti-HBsAg ScFv. ELISA assay was used to detect the antigen binding affinity of the soluble anti-HBsAg ScFv. Finally, the relative molecular mass of soluble anti-HBsAg ScFv was measured by SDS-PAGE.

RESULTS

The variable heavy (VH) and variable light (VL) and ScFv DNAs were about 340 bp, 320 bp and 750 bp, respectively. The volume of the library was up to 2 x 10(6) and 8 of 10 random clones were recombinants. Two phage clones could strongly compete with the original HBsAb for binding to HBsAg. Within 2 strong positive phage clones, the soluble anti-HBsAg ScFv from one clone was found to have the binding activity with HBsAg. SDS-PAGE showed that the relative molecular weight of soluble anti-HBsAg ScFv was 32 kDa.

CONCLUSION

The anti-HBsAg ScFv successfully produced by phage antibody technology may be useful for broadening the scope of application of the antibody.

[Fermentation and purification of Echistatin fusion protein expressed in Escherichia coli]

Lots of studies of Echistatin (Ecs) have proved its wide use in many aspects. However, the low yield of Ecs has impeded the relative researches of the protein. To establish the high-level expression system of Ecs, the fermentation and purification process of Ecs fusion protein expressed in E. coli were optimized. The Ecs gene was introduced into vector pTXB1 and placed under the control of highly efficient T7 promoter system. The cloned Ecs gene was expressed in E. coli BL21 (DE3) as soluble form. The Ecs production and biomass accumulation were optimized by examining medium composition, point of induction and induction time in fed-batch fermentation. Biomass accumulation was greatly affected by medium gradient, reaching 50.3g/L in 2 x YT medium. Ecs production was found to increase to 35% of total protein with 75g/L biomass accumulation after induced for 4h. Purification of Ecs from supernatant of sonication was done using one-step chromatographic procedure with chitin affinity chromatography and DTF cleavage, resulting in yields of 28mg/L and > 90% purity. The bioactivity of purified Ecs was determined and the result showed that purified Ecs could inhibit the aggregation of platelet in vitro with similar bioactivity to wild Ecs. This optimized method is readily scaled up for the expression and purification of Ecs in sufficient quantities for further structural and biological studies and applications.

Coexpression of interleukin-2 enhances the immunization effect of a DNA vaccine expressing herpes simplex 1 glycoprotein D

In this study, DNA vaccines consisting of vector IRES-gD expressing Herpes simplex virus 1 (HSV-1) glycoprotein D (gD) and vector IRES-gD-IL-2 coexpressing HSV-1 gD and interleukin-2 (IL-2), respectively, were constructed. After intramuscular inoculation, both vaccines induced in BALB/c mice antibodies as assayed by ELISA and virus neutralization. However, IRES-gD-IL-2 elicited significantly higher levels of IgG (ELISA) and neutralizing antibodies than IRES-gD. Isotyping of sera from mice injected with IRES-gD-IL-2 revealed predominantly IgG2a antibodies. IRES-gD-IL-2 also elicited a higher delayed-type sensitivity (DTH) reaction. However, there was no difference in the protection against lethal challenge with HSV-1 between the two vaccines (P>0.05). The results suggest that the vaccination with IRES-gD-IL-2 can efficiently enhance the immune response of mice to HSV-1, particularly through increased cellular immunity.