AIM: To study the inhibitory effects of siRNAs targeting different hTERT sequences and to screen the effective siRNA sequence.METHODS: Five double-stranded siRNAs targeting coding and non-coding regions of hTERT gene ...AIM: To study the inhibitory effects of siRNAs targeting different hTERT sequences and to screen the effective siRNA sequence.METHODS: Five double-stranded siRNAs targeting coding and non-coding regions of hTERT gene were designed and synthesized by T7 transcription system in vitro. siRNA4sequence was screened by full length gene targeting technique and the rest of the siRNA sequences were selected randomly. After being purified by ethanol precipitation, the siRNAs were transfected to the human hepatocellular carcinoma cell (HepG2) by Lipofectamine 2000TM. At 48-72 h after siRNAs transfection, MTT assay,RT-PCR and Western-blot were applied to evaluate the effects of siRNAs on cell growth, mRNA and protein expression level of hTERT gene, respectively.RESULTS: Compared to the control cells, the cells treated with the five double-stranded siRNAs exhibited different degrees of inhibition of cell proliferation in a dose-dependent manner. siRNA2 and siRNA4, exhibited obvious effects of inhibiting hTERT mRNA and protein expression in HepG2cells.CONCLUSION: siRNAs targeting different hTERT sequences have significantly various inhibitory effects on hTERT gene expression. The siRNA sequence screened by full length gene targeting technique has comparable inhibitory effect with the rest siRNA sequences screened by random selection, suggesting that siRNAs and antisense oligonucleic acids may have the same effective target sites. Compared with chemical synthesis method,synthesizing double-stranded siRNA by T7 transcription system in vitro is a rapid, simple, and inexpensive method suitable for screening high-effect siRNA targeting site for specific gene.展开更多
Objective： To investigate the molecular pathway of substance P （SP） to induce osteoblastic differentiation. Methods： Mesenchymal stem cells were isolated and cultured. The cultures were divided into four groups w...Objective： To investigate the molecular pathway of substance P （SP） to induce osteoblastic differentiation. Methods： Mesenchymal stem cells were isolated and cultured. The cultures were divided into four groups with Group A （control group） cultured without any factors, Group B cultured with SP, Group C cultured with SP and SP receptor neurokinin-1 （NK1） antagonist, and Group D cultured with SP NK1 antagonist respectively to induce osteoblastic cells differentiation. Osterix gene expression was detected by reverse transcription-polymerase chain reaction （RT-PCR） for three times after 1-2 weeks of cultivation and the results were analyzed by one-way analysis of variance （ANOVA）. Results： The log phase of bone marrow stromal cells appeared at 4-6 days. ALP staining revealed that the majority of cells, more than 95%, were positive and small bluepurple granules were found in the cytoplasm. And Group B, treated with SP, showed a higher level of ALP activity than the other three groups. Meanwhile, RT-PCR found that Osterix expression in Group B was obviously up-regulated, compared with other groups. But Osterix expression in Group D had no remarkable differences, compared with the controls. Conclusions： SP can up-regulate Osterix gene expression to stimulate differentiation of mesenchymal stem cells into osteoblastic cells at the final stage. The regulatory effect of SP on Osterix expression was dependant on SP NK1 receptors.展开更多
基金Supported by the National Natural Science Foundation of China, No. 30371662
文摘AIM: To study the inhibitory effects of siRNAs targeting different hTERT sequences and to screen the effective siRNA sequence.METHODS: Five double-stranded siRNAs targeting coding and non-coding regions of hTERT gene were designed and synthesized by T7 transcription system in vitro. siRNA4sequence was screened by full length gene targeting technique and the rest of the siRNA sequences were selected randomly. After being purified by ethanol precipitation, the siRNAs were transfected to the human hepatocellular carcinoma cell (HepG2) by Lipofectamine 2000TM. At 48-72 h after siRNAs transfection, MTT assay,RT-PCR and Western-blot were applied to evaluate the effects of siRNAs on cell growth, mRNA and protein expression level of hTERT gene, respectively.RESULTS: Compared to the control cells, the cells treated with the five double-stranded siRNAs exhibited different degrees of inhibition of cell proliferation in a dose-dependent manner. siRNA2 and siRNA4, exhibited obvious effects of inhibiting hTERT mRNA and protein expression in HepG2cells.CONCLUSION: siRNAs targeting different hTERT sequences have significantly various inhibitory effects on hTERT gene expression. The siRNA sequence screened by full length gene targeting technique has comparable inhibitory effect with the rest siRNA sequences screened by random selection, suggesting that siRNAs and antisense oligonucleic acids may have the same effective target sites. Compared with chemical synthesis method,synthesizing double-stranded siRNA by T7 transcription system in vitro is a rapid, simple, and inexpensive method suitable for screening high-effect siRNA targeting site for specific gene.
文摘Objective： To investigate the molecular pathway of substance P （SP） to induce osteoblastic differentiation. Methods： Mesenchymal stem cells were isolated and cultured. The cultures were divided into four groups with Group A （control group） cultured without any factors, Group B cultured with SP, Group C cultured with SP and SP receptor neurokinin-1 （NK1） antagonist, and Group D cultured with SP NK1 antagonist respectively to induce osteoblastic cells differentiation. Osterix gene expression was detected by reverse transcription-polymerase chain reaction （RT-PCR） for three times after 1-2 weeks of cultivation and the results were analyzed by one-way analysis of variance （ANOVA）. Results： The log phase of bone marrow stromal cells appeared at 4-6 days. ALP staining revealed that the majority of cells, more than 95%, were positive and small bluepurple granules were found in the cytoplasm. And Group B, treated with SP, showed a higher level of ALP activity than the other three groups. Meanwhile, RT-PCR found that Osterix expression in Group B was obviously up-regulated, compared with other groups. But Osterix expression in Group D had no remarkable differences, compared with the controls. Conclusions： SP can up-regulate Osterix gene expression to stimulate differentiation of mesenchymal stem cells into osteoblastic cells at the final stage. The regulatory effect of SP on Osterix expression was dependant on SP NK1 receptors.
