[Changes in expressions of sRNA SpR19 and its potential target GroEL in Streptococcus mutans strains with different cariogenicity cultured under different pH conditions].

OBJECTIVE: To investigate the changes in the expression level of sRNA SpR19 and its potential target protein GroEL in clinical isolates of Streptococcus mutans with different cariogenicity exposed to different pH conditions and explore the possibility of using these molecules as biomarkers for assessing the cariogenicity of the bacteria. METHODS: The total RNAs were extracted from the clinical isolates of Streptococcus mutans with high (strain 17) and low cariogenicity (strain 5) for high-throughput sequencing for profiling of the differentially expressed sRNAs. The candidate sRNA, SpR19, was selected for further study on the basis of bioinformatics analysis considering the role of its potential target in the cariogenic process. The differential expression levels of SpR19 in the strains exposed to both pH5.5 and pH7 culture conditions were verified by quantitative real-time PCR. The expression of the potential target of SpR19, GroEL, was also investigated at both the protein and mRNA level using Western blotting and quantitative real-time PCR. RESULTS: Bioinformatic analysis suggested multiple potential target sites of SpR19 both in GroEL mRNA and in the upstream and downstream inter-genic regions. Under different pH conditions, the highly cariogenic strain 17 expressed consistently low levels of SpR19 as compared with the strain 5 with a low cariogenicity; GroEL showed a reverse expression pattern in the 2 strains. An inverse correlation was found between the expressions of SpR19 and GroEL. CONCLUSION: The highly cariogenic strain 17 expressed low levels of SpR19 and high levels of GroEL in both acidic and neutral culture conditions. SpR19 may negatively regulate the cariogenicity of Streptococcus mutants by targeting at GroEL.

Effect of Cbfa1 on osteogenic differentiation of mesenchymal stem cells under hypoxia condition.

OBJECTIVE: To observe the effect of Cbfa1 on biological characteristics of marrow mesenchymal stem cells under hypoxia. METHODS: The second passage of the MSCs were transfected with Cbfa1 and then cultured in 20% O2 and 3% O2 condition individually. The biological features of the cultured MSCs were assessed by the Real-time PCR. RESULTS: After transfected with Cbfa1, the morphology of MSCs was no significant difference between two oxygen concentrations; The RT-PCR examination revealed that the expression of Cbfa1, BMP, OPN and VEGF in MSCs was higher than those before Cbfa1 transfection (P<0.05), especial the expression of Cbfa1 (P<0.05). CONCLUSION: After transfected with Cbfa1, cell morphology or growth cycle of MSCs was not significantly affected, but its osteogenic differentiation potential enhanced, particularly its osteogenic differentiation potential under hypoxia enhanced.

Intravenous transplantation of allogeneic bone marrow mesenchymal stem cells and its directional migration to the necrotic femoral head.

In this study, we investigated the feasibility and safety of intravenous transplantation of allogeneic bone marrow mesenchymal stem cells (MSCs) for femoral head repair, and observed the migration and distribution of MSCs in hosts. MSCs were labeled with green fluorescent protein (GFP) in vitro and injected into nude mice via vena caudalis, and the distribution of MSCs was dynamically monitored at 0, 6, 24, 48, 72 and 96 h after transplantation. Two weeks after the establishment of a rabbit model of femoral head necrosis, GFP labeled MSCs were injected into these rabbits via ear vein, immunological rejection and graft versus host disease were observed and necrotic and normal femoral heads, bone marrows, lungs, and livers were harvested at 2, 4 and 6 w after transplantation. The sections of these tissues were observed under fluorescent microscope. More than 70 % MSCs were successfully labeled with GFP at 72 h after labeling. MSCs were uniformly distributed in multiple organs and tissues including brain, lungs, heart, kidneys, intestine and bilateral hip joints of nude mice. In rabbits, at 6 w after intravenous transplantation, GFP labeled MSCs were noted in the lungs, liver, bone marrow and normal and necrotic femoral heads of rabbits, and the number of MSCs in bone marrow was higher than that in the, femoral head, liver and lungs. Furthermore, the number of MSCs peaked at 6 w after transplantation. Moreover, no immunological rejection and graft versus host disease were found after transplantation in rabbits. Our results revealed intravenously implanted MSCs could migrate into the femoral head of hosts, and especially migrate directionally and survive in the necrotic femoral heads. Thus, it is feasible and safe to treat femoral head necrosis by intravenous transplantation of allogeneic MSCs.

Small ncRNA expression and regulation under hypoxia in neural progenitor cells.

Small non-coding RNA (ncRNA) plays critical roles in a large number of cellular processes, including neural development, cell survival and cell determination. Our previous work showed that low oxygen promoted the survival and proliferation of neural progenitor cells (NPCs) in vitro. In this study, we examine the expression and regulation of small ncRNAs in the hypoxia-driven proliferation of NPCs. The expression profiles of ncRNAs in NPCs under hypoxia were detected using microarray analysis. Results of significance analysis of microarrays (SAM) revealed that 15 small RNAs were up-regulated at least threefold and 11 were down-regulated under hypoxic conditions. The differentially expressed small ncRNAs were confirmed by quantitative RT-PCR, and miR-210 was observed to be highly expressed in NPCs under hypoxic conditions. Further study showed that hypoxia-inducible factor (HIF)-1α had a direct impact on the putative promoter regions of miR-210. From these results, we conclude that some small ncRNAs participate in the regulation of the proliferation of NPCs under hypoxia and that miR-210 is directly regulated by HIF-1α.

[Expression of microRNAs in endometrioid adenocarcinoma].

OBJECTIVE: To analyze miRNA expression profile of endometrioid adenocarcinoma. METHODS: Collect Endometrium was collected from cancer and park cancer tissue. And the total RNA was extracted. The microarray detection system was employed to analyze whether there was difference in microRNA expression between cancer tissue and park cancer tissue. RESULTS: A total of 111 differentially expressed miRNA were found, including 68 over-expression miRNA and 43 low-expression. CONCLUSION: MiRNA may play important roles in tumorigenesis of endometrioid adenocarcinoma. The study of miRNA contributes to elucidate the molecular mechanism of endometrial cancer.

[Transfer RNAs inhibit the growth of L929 cells in vitro].

AIM: To explore the effects of tRNA on the growth of mammalian cells. METHODS: L929, NIH3T3, MCF-7 and PC12 cells were seeded in 96 well culture plate individually, and incubated at 37 degrees C in 5% CO2 for 4 h, the tRNAs from different species were added to the culture media individually. After certain time of incubation, the viability of the cells was evaluated by the MTT methods. Sub-confluent L929 cells were incubated with 200 microg/ml ytRNA for different times, then the cells were pooled and analyzed with flow cytometry assay. RESULTS: tRNA specifically inhibited the growth of L929 cells in a dose-dependent manner. The sizes of tRNA-treated cells showed larger sizes and longer processes than those of untreated cells. Flow cytometric analysis further showed that most of tRNA-treated cells were arrested in S phase of the cell cycle. CONCLUSION: The cell growth inhibitory effects of tRNAs were caused mainly by their degraded fragments. The results suggested that tRNA or its degraded fragments might play important roles in regulation of cell proliferation.

Selection of novel nickel-binding peptides from flagella displayed secondary peptide library.

Nickel (Ni) performs its biological or toxic functions in nickel-protein coordination form. Novel Ni-binding peptides were isolated from a random dodecapeptide library displayed on the flagella of Escherichia coli against immobilized ions. On the basis of isolated sequences rich in histidine residues, two secondary libraries were constructed respectively. By consequent selection, more Ni-chelating peptides were identified and the consensus motif RHXHR (where X was always H) was deduced. The result suggested that not only histidine, but also arginine, play an important role in Ni-binding. Furthermore, two selected clones (1035 and 2022) were chosen for further identification. They exhibited similar relative binding affinity, which was about nine times that of the original library derived clones and statistically much more significant than the positive control with polyhistidine insert. Free nickel ions could almost completely inhibit the binding of the clones 1035 and 2022 to immobilized nickel, implicating that the peptides were able to chelate nickel ions. These studies reveal that bacterial surface displayed peptide libraries may have promising future potential for the development of metal bioadsorbents. Furthermore, novel Ni-binding peptides may provide lead molecules for Ni-chelation and applications thereof.

[Preliminary study on change of serum proteome in noxious heat blood stasis syndrome treated by radix Paeoniae rubra].

OBJECTIVE: To study the effect of red peony root (RPR) on serum proteome in rat suffering from noxious heat with blood stasis Syndrome (NH-BS). METHODS: The differences of serum proteome among rats in four groups, treated with lipopolysaccharide (LPS), RPR, LPS + RPR and saline respectively, were analyzed by bi-dimensional electrophoresis (2DE) assay. LPS was administered by intravenous injection and RPR by oral intake. RESULTS: (1) Serum of rats with LPS induced NH-BS showed significant changes in volume of serum protein (xPr) in 13 points on 2DE collagen, the volume of xPr 16 and 19 were significantly lower, volume of xPr 1, 2, 3, 4, 6, 7, 8, 9, 11, 12 and 23 were significantly higher respectively, as compared with those in the normal control group. (2) After being treated with RPR, the increased volume of xPr 1, 2, 3, 4 and 9 significantly decreased, and the decreased xPr 16 significantly increased, with xPr 2, 3 restored to normal level but the xPr16 still lower and xPr 1, 4, 9 higher than those in the normal group. RPR showed interaction with LPS on xPr 1, 3, 9, and 16. (3) For xPr 19, the interaction of RPR with LPS might be synergistic. (4) In the group treated with RPR, volumes of xPr 13 and 14 were significantly higher and those of 15, 17 were significantly lower than those in the normal group respectively, but the similar changes didn't found in the LPS group. CONCLUSION: The molecular basis of therapeutic effect of RPR on NH-BS might be through the regulation of xPr 1, 2, 3, 4, 9 and 16.

[Study on serum proteome of rat endotoxemia treated by figwort root].

OBJECTIVE: To study the serum proteome of rat endotoxemia treated by figwort root (FR). METHOD: The differences of serum proteome among rats treated with lipopolysaccharide (LPS), FR, LPS + FR and saline respectively were analyzed by two-dimensional electrophoresis (2DE) assay. RESULT: The volumes of sixteen serum proteins (xPr) in LPS induced-endotoxemia group were greatly changed compared with those of the control group. Among them, the volumes of xPr 16, 19 were significantly decreased, and the volumes of xPr 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 14, 18, 23 were significantly increased. When treated with FR, the volumes of xPr 1, 6, 7, 8, 9, 11, 12, 14, 18, 23 were significantly decreased, and the volumes of xPr 8, 9, 11, 12, 23, 14 were back to normal level. Two factors statistic analysis showed that FR had interaction with LPS for xPr 1, 5, 8, 10, 11, 12, 18, 19, 20, 21, 22, and FR might be the functional antagonist of LPS. We also observed that the volumes of xPr 10, 13, 15, 20, 21, 22 were found to change significantly only in FR treated group but not in LPS treated group or control group. Interestingly, the volume of xPr 13, 20, 21, 22 were increased and the volume of xPr 10, 15 were decreased. CONCLUSION: The molecular basis of therapeutic effect of FR on endotoxemia might be through the regulation of xPr 1, 6, 7, 8, 9, 11, 12, 14, 18, 23. We can use proteomic techniques to study the molecular mechanisms of diseases treated by functional Chinese herbs and the combination of different herbs is necessary for the treatment of endotoxemia, as FR can not regulated all the changed proteins induced by LPS.

A subtractive fluorescence-activated cell-sorting strategy to identify mimotopes of HBV-preS protein from bacterially displayed peptide library.

A novel subtractive fluorescence-activated cell-sorting (FACS) strategy using a model system is described here to identify disease-specific (DS) epitopes from a bacterially displayed random peptide library. In this process, preimmune serum was used as "Driver " to block any common binding sites on the bacterial surface and the labeled anti-preS IgG polyclonal antibodies from immunized serum were used as "Tester" to enrich preS-specific mimotopes. Bacterial clones were identified out of this pool through an "antigen-independent" procedure only using both different sera samples. After four rounds of sub-FACS screening, 41 out of 50 bacterial clones were identified as reacting with the immunized serum but not reacting with the pre-immune one. Two motif sequences HQLD and DPAF were obtained from 13 clones. Immunization of mice with two representative bacterial clones elicited a strong specific response against native preS antigen in comparison with the control. This technique may provide a useful technology platform for high-throughput screening of disease-related epitope which is of importance to develop vaccine against some infectious diseases whose pathogen or immunodominant antigen is still unknown.

Identification of anti-TNFalpha peptides with consensus sequence.

Phage displayed peptide library was used to select tumor necrosis factor alpha (TNFalpha) binding peptides. After three sequential rounds of biopanning, some linear TNFalpha-binding peptides were identified from a 12-mer peptide library. A consensus sequence (L/M)HEL(Y/F)(L/M)X(W/Y/F), where X might be variable residue, was deduced from sequences of these peptides. The phages bearing these peptides showed specific binding to immobilized TNFalpha, with over 80% of phages bound being competitively eluted by free TNFalpha. To confirm the binding activity and to explore further functional properties, three peptides with typical structure were selected and expressed as GST-fused protein. These recombinant peptides effectively competed for [125I]TNFalpha binding to TNFR1 in a dose-dependent manner, with IC(50) from 10 to 160 microM. Furthermore, the GST-fused derivatives showed inhibitory effects on TNFalpha-induced cytotoxicity. Taken together, these data demonstrate that the TNFalpha-binding peptides are effective antagonists of TNFalpha and the deduced motif might be useful in development of novel low molecular weight anti-TNFalpha drugs.

Specific oligobodies against human brain acetylcholinesterase.

In order to develop the specific oligobodies against human brain acetylcholinesterase (AChE) and distinguishes between human erythrocyte and brain AChEs, we applied the strategy of 'target switching' to obtain the specific polyclonal and monoclonal oligobodies. The specificity between human brain AChE and other ChEs was identified by Western blotting, dot blotting and enzyme protein binding assay (EPBA). The results showed that the oligobodies against the human brain AChE specifically immunoreacted with the human brain AChE and Torpedo AChE, not showing significant binding to AChE from human erythrocyte and butyrylcholinesterase (BChE) from human serum.

Identification of mimotopes by screening of a bacterially displayed random peptide library and its use in eliciting an immune response to native HBV-preS.

Bacterially-displayed peptide libraries have been widely used as an alternative to phage-displayed peptide libraries in screening epitopes or mimotopes of antibodies. Using a protective monoclonal antibody (mAb) 3B9 against hepatitis B virus (HBV) preS protein as target, mimotopes were successfully screened from a FliTrx random peptide library. To monitor the enrichment ratios of each round and to isolate higher affinity clones from the library, a modified procedure was performed in which the titer of eluted bacteria from an antibody-coated well (P value) was compared with that from a non-coated well (N value). After sufficient enrichment of the library, bacterial colonies were randomly picked and identified further by the monoclonal bacterial P/N value assay and Western blotting analysis. Immunization of mice with the selected bacterially-displayed mimotopes, including the enriched populations without clone identification, elicited strong specific immune responses against the recombinant preS protein. The present study provides a potentially rapid and effective strategy for the development of engineered live bacterial vaccines without the need for information about the aetiological agents or their antigens.

Screening of RNA molecules inhibiting human acetylcholinesterase by virtue of systematic evolution of ligands by exponential enrichment.

AIM: To acquire the specific RNA aptamers inhibiting human red blood cell (RBC) acetylcholinesterase (AChE). METHODS: Systematic evolution of ligands by exponential enrichment (SELEX) aptamer against human red blood cell membrane AChE was selected by microtiter plate method in vitro. The specifity binding to AChE was determined by gel mobility shift analysis. Microcolorispectrophotometric method was used to measure the activity of AChE. RESULTS: The aptamers to human RBC AChE were identified by 9 reiterative rounds. At the same concentration (2.25 micromol/L), the aptamers did not bind to the recombinant human butyrylcholinesterase (rhBChE) but specifically bound to human RBC AChE and inhibited the enzyme activity. CONCLUSION: It is an effective way to isolate the specific AChE inhibitor from the vast oligonucleotide combinatorial library by virtue of SELEX.