AIM: To evaluate the specific inhibition of maxizyme directing against mutant-type p53 gene (mtp53) at codon 249 in exon 7 (AGG→AGT)in vitro.METHODS: Two different monomers of anti-mtp53maxizyme (maxizyme right MzR, ...AIM: To evaluate the specific inhibition of maxizyme directing against mutant-type p53 gene (mtp53) at codon 249 in exon 7 (AGG→AGT)in vitro.METHODS: Two different monomers of anti-mtp53maxizyme (maxizyme right MzR, maxizyme left MzL) and control mutant maxizyme (G5→A5) were designed by computer and cloned into vector pBSKU6 (pBSKU6MzR,pBSKU6MzL). After being sequenced, the restrictive endonuclease site in pBSKU6MzR was changed by PCR and then U6MzR was inserted into pBSKU6MzL, the recombinant vector was named pU6Mz and pU6asMz (mutant maxizyme).Mtp53 and wild-type p53 (wtp53) gene fragments were cloned into pGEN-T vector under the T7 promoter control.The 32p-labeled mtp53 transcript was the target mRNA. Cold maxizyme transcripts were incubated with 32p-labeled target RNA in vitro and radioautographed after denaturing polyacrylamide gel electrophoresis.RESULTS: In cell-free systems, pU6Mz showed a specific cleavage activity against target mRNA at 37 ℃ and 25 mM MgCL2. The cleavage efficiency of pU6Mz was 42 %, while pU6asMz had no inhibitory effect. Wtp53 was not cleaved by pU6Mz either.CONCLUSION: pU6Mz had a specific catalytic activity against mtp53 in cell-free system. These lay a good fundation for studying the effects of anti-mtp53 maxizyme in HCC cell lines. The results suggest that maxizyme may be a promising alternative approach for treating hepatocellular carcinoma containing mtp53.展开更多
AIM:To prepare and identify specific anti-mouse caspase-12 hammerhead ribozymes in vitro, in order to select a more effective ribozyme against mouse caspase-12 as a potential tool to rescue cells from endoplasmic reti...AIM:To prepare and identify specific anti-mouse caspase-12 hammerhead ribozymes in vitro, in order to select a more effective ribozyme against mouse caspase-12 as a potential tool to rescue cells from endoplasmic reticulum stress induced apoptosis. METHODS: Two hammerhead ribozymes directed separately against 138 and 218 site of nucleotide of mouse caspase-12 mRNA were designed by computer software, and their DNA sequences were synthesized. The synthesized ribozymes were cloned into an eukaryotic expression vector-neorpBSKU6 and embedded in U6 SnRNA context for further study. Mouse caspase-12 gene segment was cloned into PGEM-T vector under the control of T7 RNA polymerase promoter (containing gene sequence from positions nt 41 to nt 894) as target. In vitro transcription both the ribozymes and target utilize T7 promoter. The target was labeled with [α-32P]UTP, while ribozymes were not labeled. After gel purification the RNAs were dissolved in RNase free water. Ribozyme and target were incubated for 90 min at 37 ℃ in reaction buffer (40 mmol/L Tris-HCL, pH 7.5, 10 mmol/L Mg2+). Molar ratio of ribozyme vs target was 30:1. Samples were analyzed on 6% PAGE (containing 8 mol/L urea). RESULTS: Both caspase-12 and ribozyme gene sequences were successfully cloned into expression vector confirmed by sequencing. Ribozymes and caspase-12 mRNA were obtained by in vitro transcription. Cleavage experiment showed that in a physiological similar condition (37 ℃, pH 7.5), Rz138 and Rz218 both cleaved targets at predicted sites, for Rz138 the cleavage efficiency was about 100%, for Rz218 the value was 36.66%. CONCLUSION: Rzl38 prepared in vitro can site specific cleave mouse caspase-12 mRNA with an excellent efficiency. It shows a potential to suppress the expression of caspase-12 in vivo, thus provided a new way to protect cells from ER stress induced apoptosis.展开更多
AIM:To prepare hammerhead ribozymes against mouse caspase-7 and identify their cleavage activity in vitro, in order to select a ribozyme with specific cleavage activity against mouse caspase-7 as a potential gene ther...AIM:To prepare hammerhead ribozymes against mouse caspase-7 and identify their cleavage activity in vitro, in order to select a ribozyme with specific cleavage activity against mouse caspase-7 as a potential gene therapy for apoptosis-related diseases.METHODS: Anti-caspase-7 ribozymes targeting sites 333 and 394 (named Rz333 and Rz394) were designed by computer software, and their DNA sequences encoding ribozymes were synthesized. Caspase-7 DNA sequence was acquired by RT-PCR. Ribozymes and caspase-7 DNA obtained by in vitro transcription were cloned into pBSKneo U6′ and pGEM-T vectors, respectively. The cleavage activity of ribozymes against mouse caspase-7 was identified by cleavage experiments in vitro.RESULTS: Rz333 and Rz394 were designed and their DNA sequences were synthesized respectively. The expression vector of caspase-7 and plasmids containing Rz333 and Rz394 were reconstructed successfully. Ribozymes and caspase-7 mRNA were expressed by in vitro transcription.In vitro cleavage experiment showed that 243-nt and 744-nt segments were produced after caspase-7 mRNA was mixed with Rz333 in equivalent, and the cleavage efficiency was 67.98%. No cleaved segment was observed when caspase-7 mRNA was mixed with Rz394.CONCLUSION: Rz333 can site-specific cleave mouse caspase-7 mRNA, and it shows a potential for gene therapy of apoptosis-related diseases by down-regulating gene expression of caspase-7.展开更多
AIM: To investigate the designation, synthesis and biological activity of against vascular endothelial growth factor165 (VEGF165) ribozyme.METHODS: The ribozyme against VEGF165 was designed with computer. The transcri...AIM: To investigate the designation, synthesis and biological activity of against vascular endothelial growth factor165 (VEGF165) ribozyme.METHODS: The ribozyme against VEGF165 was designed with computer. The transcriptional vector was constructed which included the anti-VEGF165 ribozyme and 5', 3' selfsplicing ribozymes. The hammerhead ribozyme and substrate VEGF165 mRNA were synthesized through transcription in vitro.The cleavage activity of the ribozyme on target RNA was observed in a cell-free system.PESULTS: The anti-VEGF165 ribozyme was released properly from the transcription of pGEMRz212 cleaved by 5' and 3' self-splicing ribozymes which retained its catalytic activity,and the cleavage efficiency of ribozyme reached 90.7%.CONCLUSION: The anti-VEGF165 ribozyme designed with computer can cleave VEGF165 mRNA effectively.展开更多
The natural gonadotropin-releasing hormone ( GnRH ) is apt to be degraded by the peptidascs. In addition, the low level of GnRH in the peripheral circulation makes it diffucult to measure.
The steady state of mRNAs for the α-and βA-subunits of inhibin was investigated in human corpora lutea(CL) during the menstrual cycle by Northern blot analysis with more sensitive cRNA probes. It revealed α 1.6kb m...The steady state of mRNAs for the α-and βA-subunits of inhibin was investigated in human corpora lutea(CL) during the menstrual cycle by Northern blot analysis with more sensitive cRNA probes. It revealed α 1.6kb mRNA for a subunit and 6.0,4.0, 2.8 and 1.8kb transcripts for βA subunit, Both of α-and βA inhibin mRNAs were detectable in CLs during early, mid and late luteal phases, but not in retrogressive CL after day-27 of the cycle or in tissues of ovarian stroma. An overall profile of展开更多
Objective. The goal of this paper is to investigate the relationship between the N-glycosylation of acetylglucosaminyltransferase V(Glc NAcT-V) and its activity and to know which site among the 6 N-glycosylation sites...Objective. The goal of this paper is to investigate the relationship between the N-glycosylation of acetylglucosaminyltransferase V(Glc NAcT-V) and its activity and to know which site among the 6 N-glycosylation sites in the GlcNAcT-V gene is the most important. Methods.Wild type of GlcNAcTV was transfected into COS7 cells and its activity was measured 48 h later. The first site (Asn 110) was mutated with sitedirected mutagenesis and transfected into COS7 cells. Results. It was found that after the cells were added tunicamycin(TM, 1 μ g/ml), the activity was 117% of the wild type. The activity of the cells with mutating GlcNAcTV was about 120% of the wild type RTPCR showed that there was no significant change in mRNA expression among the three groups. Conclusion.The Nglycosylation is important for its activity. Our results suggest that the Nlinked carbohydrates on GlcNAcTV are required for the posttranscriptional activity of the enzyme.展开更多
A hammerhead ribozyme which site-specifically cleaved the GUC position in canon 880 of the mdr1 mRNA was designed. The target site was chosen between the two ATP binding sites, which may be important for the function ...A hammerhead ribozyme which site-specifically cleaved the GUC position in canon 880 of the mdr1 mRNA was designed. The target site was chosen between the two ATP binding sites, which may be important for the function of the P-Gp as an ATP-dependent pump. A DNA sequence encoding the ribozyme gene was then incorporated into a eukaryotic expression vector (pH Apr-1 neo) and transfected into the breast cancer cell line MCF-7/Adr, which is resistant to adriamycin and expresses the MDR phenotype. The ribozyme was stably expressed in the cell line by the RNA dot blotting assay. The result of Northern blot assay showed that the expressed ribozyme could decrease the level of mdrl mRNA expression by 83. 5 %; and the expressed ribozyme could inhibite the formation of p-glycoprotein detected by immuno- cy-tochemistry assay and could reduce the cell’s resistance to adrimycin; this means that the resistant cells were 1 000-fold more resistant than the parental cell line(MCF-7), whereas those cell clones that showed ribozyme expression were only 6-fold more resistant than the parental cell line. These results show that a potentially useful tool is at hand which may inactivate MDR1 mRNA and revert the multidrug resistance phenotype.展开更多
Theeffects of gonadotrophin--relensing hormone (GnRH) onthe bindingof^125I-labelled GnRH agonist to human placental membranes were studied. The GnRH binding sites of human plaoenta had a high specificity but low affin...Theeffects of gonadotrophin--relensing hormone (GnRH) onthe bindingof^125I-labelled GnRH agonist to human placental membranes were studied. The GnRH binding sites of human plaoenta had a high specificity but low affinity. The natural GnRH had a展开更多
A synthetic oligonucleotide, HSD-2a, encoding a peptide segment of the extracel-lular domain of a human sperm membrane protein, YWK-II, was fused with hepatitisB surface antigen gene (HBs gene ). The fused gene was th...A synthetic oligonucleotide, HSD-2a, encoding a peptide segment of the extracel-lular domain of a human sperm membrane protein, YWK-II, was fused with hepatitisB surface antigen gene (HBs gene ). The fused gene was then cloned to pUC18plasmid. The fused gene was prepared from the recombinant pUC18 plasmid byBamH I and Eco R I digestion, and then cloned into the transfer vector pGJP- 5 underthe control of P;., promoter, designated as pGJP-HSD/HBs. CV-1 cells were co-transfected with vaccinia virus (Tian Tan strain) and pGJP-HSD/IIBs and homolo-gous re combination occurred between the vaccinia virus TK gene of the plasmid flank-ing the foreign gene and the same sequences within the virus genome. TK phen0tyPerecombinant virus, vv-HSD/HBs, were selected from trandected HuTK' cells byplaque purthcation technique. The eopressi0n of HSD-b in spent medium and cellu-lar protein of HuTK cells infected with vv-HSD/HBs was determined by ELISAand Western-blot analysis using anti-rwK-II antiserum. The present study indicatesthat the vv-HSD/HBs seems promising as an antdertility vaccine.展开更多
The correlation or serum estradiol concentrstion and uterine estrogen receptor (ER) gene expression (ERn and ERc quantitated by Dextrsn Coat Charcoal assay and ER mRNA by Northern blotting) was studied during the rat ...The correlation or serum estradiol concentrstion and uterine estrogen receptor (ER) gene expression (ERn and ERc quantitated by Dextrsn Coat Charcoal assay and ER mRNA by Northern blotting) was studied during the rat estrous cycle and early Pregnant stage (dl-d10). The ER gone expression was up - regulated by estrogen and the levels of ER mRNA synchronized with the changes of ER protein, suggesting that estrogen influenced the trsnscriPtional step of the ER gene. Post-coitum ER expression increased with the serum estrsdiol progressively, reached a peak on d4-ds (Just before implantation), but drastically dropped to the nadir on d6-d7 (during implantation) and then recovered. It was of interest to discover that ER mRNA level in the nonimplantstion sites (NIS) of uterus was much higher than that in the implantstion sites (IS).展开更多
Background Activation and proliferation of hepatic stellate cells (HSC) is essentially involved in the development and progression of hepatic fibrosis. The most potent growth factor for HSC is platelet-derived growth...Background Activation and proliferation of hepatic stellate cells (HSC) is essentially involved in the development and progression of hepatic fibrosis. The most potent growth factor for HSC is platelet-derived growth factor receptor (PDGF) and PDGF receptor β subunit (PDGFR-β) is the predominant signal transduction pathyway of PDGF which is overexpressed in activated HSC. This study investigated the cleavage activity of hammerhead ribozyme targeting PDGFR-β mRNA in HSC and the effect on biological characteristics of HSC.Methods Expression vector of anti-PDGFR-β ribozyme was constructed and transfected into rat activated HSC with lipofectamin. The positive cell clones were gained by G418 selection. The expression of PDGFR-β, α-smooth muscle actin, and typeⅠand type Ⅲ collagen were detected by using Northern blot, Western blot and immunocytochemical staining, respectively. The cell proliferation was determined with MTT colorimetric assay. The cell apoptosis was analyzed by using flow cytometry, acridine orange fluorescence vital staining and transmission electron microscopy.Results The expression of PDGFR-β at mRNA and protein level was markedly reduced in ribozyme-transfected HSC by 49%-57% ( P <0.05-0.01). The proliferation and α-smooth muscle actin expression of ribozyme-transfected HSC were significantly decreased ( P <0.05-0.01), and the type Ⅰ and type Ⅲ collagen synthesis were also reduced ( P <0.01). In addition, the proliferative response of ribozyme-transfected HSC to PDGF BB was significantly inhibited. Otherwise, the apoptotic cells were significantly increased in ribozyme-transfected HSC ( P <0.01), and typical apoptotic cells could be found under transmission electron microscopy.Conclusions The anti-PDGFR-β ribozyme effectively cleaved the target RNA and significantly inhibited its expression, which blocked the signal transduction of PDGF at receptor level, inhibited HSC proliferation and collagen synthesis, and induced HSC apoptosis. These results suggest that inhibiting PDGFR-β expression of HSC may be a new target for the therapy of liver fibrogenesis, and ribozyme may be a useful tool for inhibiting PDGFR-β expression.展开更多
基金the National Natural Science Foundation of China,No.30171061
文摘AIM: To evaluate the specific inhibition of maxizyme directing against mutant-type p53 gene (mtp53) at codon 249 in exon 7 (AGG→AGT)in vitro.METHODS: Two different monomers of anti-mtp53maxizyme (maxizyme right MzR, maxizyme left MzL) and control mutant maxizyme (G5→A5) were designed by computer and cloned into vector pBSKU6 (pBSKU6MzR,pBSKU6MzL). After being sequenced, the restrictive endonuclease site in pBSKU6MzR was changed by PCR and then U6MzR was inserted into pBSKU6MzL, the recombinant vector was named pU6Mz and pU6asMz (mutant maxizyme).Mtp53 and wild-type p53 (wtp53) gene fragments were cloned into pGEN-T vector under the T7 promoter control.The 32p-labeled mtp53 transcript was the target mRNA. Cold maxizyme transcripts were incubated with 32p-labeled target RNA in vitro and radioautographed after denaturing polyacrylamide gel electrophoresis.RESULTS: In cell-free systems, pU6Mz showed a specific cleavage activity against target mRNA at 37 ℃ and 25 mM MgCL2. The cleavage efficiency of pU6Mz was 42 %, while pU6asMz had no inhibitory effect. Wtp53 was not cleaved by pU6Mz either.CONCLUSION: pU6Mz had a specific catalytic activity against mtp53 in cell-free system. These lay a good fundation for studying the effects of anti-mtp53 maxizyme in HCC cell lines. The results suggest that maxizyme may be a promising alternative approach for treating hepatocellular carcinoma containing mtp53.
基金Supported by the National Natural Science Foundation of China, No. 30170850Shanghai Education Foundation
文摘AIM:To prepare and identify specific anti-mouse caspase-12 hammerhead ribozymes in vitro, in order to select a more effective ribozyme against mouse caspase-12 as a potential tool to rescue cells from endoplasmic reticulum stress induced apoptosis. METHODS: Two hammerhead ribozymes directed separately against 138 and 218 site of nucleotide of mouse caspase-12 mRNA were designed by computer software, and their DNA sequences were synthesized. The synthesized ribozymes were cloned into an eukaryotic expression vector-neorpBSKU6 and embedded in U6 SnRNA context for further study. Mouse caspase-12 gene segment was cloned into PGEM-T vector under the control of T7 RNA polymerase promoter (containing gene sequence from positions nt 41 to nt 894) as target. In vitro transcription both the ribozymes and target utilize T7 promoter. The target was labeled with [α-32P]UTP, while ribozymes were not labeled. After gel purification the RNAs were dissolved in RNase free water. Ribozyme and target were incubated for 90 min at 37 ℃ in reaction buffer (40 mmol/L Tris-HCL, pH 7.5, 10 mmol/L Mg2+). Molar ratio of ribozyme vs target was 30:1. Samples were analyzed on 6% PAGE (containing 8 mol/L urea). RESULTS: Both caspase-12 and ribozyme gene sequences were successfully cloned into expression vector confirmed by sequencing. Ribozymes and caspase-12 mRNA were obtained by in vitro transcription. Cleavage experiment showed that in a physiological similar condition (37 ℃, pH 7.5), Rz138 and Rz218 both cleaved targets at predicted sites, for Rz138 the cleavage efficiency was about 100%, for Rz218 the value was 36.66%. CONCLUSION: Rzl38 prepared in vitro can site specific cleave mouse caspase-12 mRNA with an excellent efficiency. It shows a potential to suppress the expression of caspase-12 in vivo, thus provided a new way to protect cells from ER stress induced apoptosis.
基金Supported by the National Natural Science Foundation of China,No.30170850
文摘AIM:To prepare hammerhead ribozymes against mouse caspase-7 and identify their cleavage activity in vitro, in order to select a ribozyme with specific cleavage activity against mouse caspase-7 as a potential gene therapy for apoptosis-related diseases.METHODS: Anti-caspase-7 ribozymes targeting sites 333 and 394 (named Rz333 and Rz394) were designed by computer software, and their DNA sequences encoding ribozymes were synthesized. Caspase-7 DNA sequence was acquired by RT-PCR. Ribozymes and caspase-7 DNA obtained by in vitro transcription were cloned into pBSKneo U6′ and pGEM-T vectors, respectively. The cleavage activity of ribozymes against mouse caspase-7 was identified by cleavage experiments in vitro.RESULTS: Rz333 and Rz394 were designed and their DNA sequences were synthesized respectively. The expression vector of caspase-7 and plasmids containing Rz333 and Rz394 were reconstructed successfully. Ribozymes and caspase-7 mRNA were expressed by in vitro transcription.In vitro cleavage experiment showed that 243-nt and 744-nt segments were produced after caspase-7 mRNA was mixed with Rz333 in equivalent, and the cleavage efficiency was 67.98%. No cleaved segment was observed when caspase-7 mRNA was mixed with Rz394.CONCLUSION: Rz333 can site-specific cleave mouse caspase-7 mRNA, and it shows a potential for gene therapy of apoptosis-related diseases by down-regulating gene expression of caspase-7.
文摘AIM: To investigate the designation, synthesis and biological activity of against vascular endothelial growth factor165 (VEGF165) ribozyme.METHODS: The ribozyme against VEGF165 was designed with computer. The transcriptional vector was constructed which included the anti-VEGF165 ribozyme and 5', 3' selfsplicing ribozymes. The hammerhead ribozyme and substrate VEGF165 mRNA were synthesized through transcription in vitro.The cleavage activity of the ribozyme on target RNA was observed in a cell-free system.PESULTS: The anti-VEGF165 ribozyme was released properly from the transcription of pGEMRz212 cleaved by 5' and 3' self-splicing ribozymes which retained its catalytic activity,and the cleavage efficiency of ribozyme reached 90.7%.CONCLUSION: The anti-VEGF165 ribozyme designed with computer can cleave VEGF165 mRNA effectively.
文摘The natural gonadotropin-releasing hormone ( GnRH ) is apt to be degraded by the peptidascs. In addition, the low level of GnRH in the peripheral circulation makes it diffucult to measure.
文摘The steady state of mRNAs for the α-and βA-subunits of inhibin was investigated in human corpora lutea(CL) during the menstrual cycle by Northern blot analysis with more sensitive cRNA probes. It revealed α 1.6kb mRNA for a subunit and 6.0,4.0, 2.8 and 1.8kb transcripts for βA subunit, Both of α-and βA inhibin mRNAs were detectable in CLs during early, mid and late luteal phases, but not in retrogressive CL after day-27 of the cycle or in tissues of ovarian stroma. An overall profile of
文摘Objective. The goal of this paper is to investigate the relationship between the N-glycosylation of acetylglucosaminyltransferase V(Glc NAcT-V) and its activity and to know which site among the 6 N-glycosylation sites in the GlcNAcT-V gene is the most important. Methods.Wild type of GlcNAcTV was transfected into COS7 cells and its activity was measured 48 h later. The first site (Asn 110) was mutated with sitedirected mutagenesis and transfected into COS7 cells. Results. It was found that after the cells were added tunicamycin(TM, 1 μ g/ml), the activity was 117% of the wild type. The activity of the cells with mutating GlcNAcTV was about 120% of the wild type RTPCR showed that there was no significant change in mRNA expression among the three groups. Conclusion.The Nglycosylation is important for its activity. Our results suggest that the Nlinked carbohydrates on GlcNAcTV are required for the posttranscriptional activity of the enzyme.
基金This research was supported by the National Natural ScienceYouth Grant.
文摘A hammerhead ribozyme which site-specifically cleaved the GUC position in canon 880 of the mdr1 mRNA was designed. The target site was chosen between the two ATP binding sites, which may be important for the function of the P-Gp as an ATP-dependent pump. A DNA sequence encoding the ribozyme gene was then incorporated into a eukaryotic expression vector (pH Apr-1 neo) and transfected into the breast cancer cell line MCF-7/Adr, which is resistant to adriamycin and expresses the MDR phenotype. The ribozyme was stably expressed in the cell line by the RNA dot blotting assay. The result of Northern blot assay showed that the expressed ribozyme could decrease the level of mdrl mRNA expression by 83. 5 %; and the expressed ribozyme could inhibite the formation of p-glycoprotein detected by immuno- cy-tochemistry assay and could reduce the cell’s resistance to adrimycin; this means that the resistant cells were 1 000-fold more resistant than the parental cell line(MCF-7), whereas those cell clones that showed ribozyme expression were only 6-fold more resistant than the parental cell line. These results show that a potentially useful tool is at hand which may inactivate MDR1 mRNA and revert the multidrug resistance phenotype.
文摘Theeffects of gonadotrophin--relensing hormone (GnRH) onthe bindingof^125I-labelled GnRH agonist to human placental membranes were studied. The GnRH binding sites of human plaoenta had a high specificity but low affinity. The natural GnRH had a
文摘A synthetic oligonucleotide, HSD-2a, encoding a peptide segment of the extracel-lular domain of a human sperm membrane protein, YWK-II, was fused with hepatitisB surface antigen gene (HBs gene ). The fused gene was then cloned to pUC18plasmid. The fused gene was prepared from the recombinant pUC18 plasmid byBamH I and Eco R I digestion, and then cloned into the transfer vector pGJP- 5 underthe control of P;., promoter, designated as pGJP-HSD/HBs. CV-1 cells were co-transfected with vaccinia virus (Tian Tan strain) and pGJP-HSD/IIBs and homolo-gous re combination occurred between the vaccinia virus TK gene of the plasmid flank-ing the foreign gene and the same sequences within the virus genome. TK phen0tyPerecombinant virus, vv-HSD/HBs, were selected from trandected HuTK' cells byplaque purthcation technique. The eopressi0n of HSD-b in spent medium and cellu-lar protein of HuTK cells infected with vv-HSD/HBs was determined by ELISAand Western-blot analysis using anti-rwK-II antiserum. The present study indicatesthat the vv-HSD/HBs seems promising as an antdertility vaccine.
文摘The correlation or serum estradiol concentrstion and uterine estrogen receptor (ER) gene expression (ERn and ERc quantitated by Dextrsn Coat Charcoal assay and ER mRNA by Northern blotting) was studied during the rat estrous cycle and early Pregnant stage (dl-d10). The ER gone expression was up - regulated by estrogen and the levels of ER mRNA synchronized with the changes of ER protein, suggesting that estrogen influenced the trsnscriPtional step of the ER gene. Post-coitum ER expression increased with the serum estrsdiol progressively, reached a peak on d4-ds (Just before implantation), but drastically dropped to the nadir on d6-d7 (during implantation) and then recovered. It was of interest to discover that ER mRNA level in the nonimplantstion sites (NIS) of uterus was much higher than that in the implantstion sites (IS).
文摘Background Activation and proliferation of hepatic stellate cells (HSC) is essentially involved in the development and progression of hepatic fibrosis. The most potent growth factor for HSC is platelet-derived growth factor receptor (PDGF) and PDGF receptor β subunit (PDGFR-β) is the predominant signal transduction pathyway of PDGF which is overexpressed in activated HSC. This study investigated the cleavage activity of hammerhead ribozyme targeting PDGFR-β mRNA in HSC and the effect on biological characteristics of HSC.Methods Expression vector of anti-PDGFR-β ribozyme was constructed and transfected into rat activated HSC with lipofectamin. The positive cell clones were gained by G418 selection. The expression of PDGFR-β, α-smooth muscle actin, and typeⅠand type Ⅲ collagen were detected by using Northern blot, Western blot and immunocytochemical staining, respectively. The cell proliferation was determined with MTT colorimetric assay. The cell apoptosis was analyzed by using flow cytometry, acridine orange fluorescence vital staining and transmission electron microscopy.Results The expression of PDGFR-β at mRNA and protein level was markedly reduced in ribozyme-transfected HSC by 49%-57% ( P <0.05-0.01). The proliferation and α-smooth muscle actin expression of ribozyme-transfected HSC were significantly decreased ( P <0.05-0.01), and the type Ⅰ and type Ⅲ collagen synthesis were also reduced ( P <0.01). In addition, the proliferative response of ribozyme-transfected HSC to PDGF BB was significantly inhibited. Otherwise, the apoptotic cells were significantly increased in ribozyme-transfected HSC ( P <0.01), and typical apoptotic cells could be found under transmission electron microscopy.Conclusions The anti-PDGFR-β ribozyme effectively cleaved the target RNA and significantly inhibited its expression, which blocked the signal transduction of PDGF at receptor level, inhibited HSC proliferation and collagen synthesis, and induced HSC apoptosis. These results suggest that inhibiting PDGFR-β expression of HSC may be a new target for the therapy of liver fibrogenesis, and ribozyme may be a useful tool for inhibiting PDGFR-β expression.
