DNA sequence of 2.2kb of factor IX gene from each of 27 cases of Hemophilia B patients living in Jiangsu, Hubei, Shandong, Guangdong, Fujian and Ningxia provinces was studied by using the PCR (Polymerase Chain Reactio...DNA sequence of 2.2kb of factor IX gene from each of 27 cases of Hemophilia B patients living in Jiangsu, Hubei, Shandong, Guangdong, Fujian and Ningxia provinces was studied by using the PCR (Polymerase Chain Reaction) and GAWTS (Genomic Amplification with Transcript Sequencing) techniques. Twenty different mutations were found in 21 patients. Twelve of them were not reported before. Eight occured in CpG dinucleotide (38%) that was a hot spot of germ line mutations in Caucasian. No geographic specificity was found between 6 provinces. Six carriers were identified. Some advantages of the methodology were discussed.展开更多
A mutant human factor IX with arginine at 338 residual changed to alanine (hFIXR338A) by site-directed mutagenesis was introduced into AAV vectors, and a recombinant adeno-associ- ated viral vector containing hFIXR338...A mutant human factor IX with arginine at 338 residual changed to alanine (hFIXR338A) by site-directed mutagenesis was introduced into AAV vectors, and a recombinant adeno-associ- ated viral vector containing hFIXR338A, prepared by rHSV/AAV hybrid helper virus system, was directly introduced to the hind leg muscle of factor IX knock out mice. The expression and the biological activity of human factor IX mutant, hFIXR338A, and the immune response against it in the treated mice were assayed and detected. The results showed that (i) the high-level expression of human factor IX mutant protein, hFIXR338A, has been detected in rAAV-hFIXR338A treated hemophilia B mice and lasted more than 15 weeks; (ii) the clotting activity of hFIXR338A in plasma is 34.2%± 5.23%, which is remarkably higher than that of (14.27% ± 3.4%) of wild type hFIX treated mice in the activated partial thromboplastin assay; (iii) immune response against factor IX R338A was absent, with no factor IX mutant protein (hFIXR338A) inhibitors development in the treated mice; and (iv) no local or systemic side-effects and toxicity associated with the gene transfer were found. It demonstrated the potential use of treating hemophilia B by recombinant adeno-associated viral vectors with mutant hFIXR338A gene, an alternative strategy for hemophilia B gene therapy to wild-type human factor IX.展开更多
Vector GtiIX containing human clotting factor IX cDNA with intron 1 (hFIX mini-gene or Fi’IX) driven by CMV promoter was constructed based on the mini-adenoviral vector GT2073 (mini-Ad vector) with all viral protein ...Vector GtiIX containing human clotting factor IX cDNA with intron 1 (hFIX mini-gene or Fi’IX) driven by CMV promoter was constructed based on the mini-adenoviral vector GT2073 (mini-Ad vector) with all viral protein coding sequences deleted. Mini-Ad packaging cell 293Cre4 was first transduced with GTiIX, and then was transfected with helper-adenovirus AdLC8, thus mini-Ad virions AdGTiIX were obtained. At the same time, previous normal adenoviral vector pAdSPiIX containing viral genome and hFIX mini-gene was constructed, and then previous ade-novirus (pre-Ad) AdSPiIX was obtained as control. The ratio of helper-adenovirus among purified virons AdGTiIX was less than 0.8%. 3T3 cells were transfected with AdGTiIX and AdSPiIX at a MOI of 50 per cell and ELISA result showed that transient expression level in vitro was 1.4±0.2 mg /106·24 h and 1.6±0.3 mg/106·24 h respectively. Each hemophilia B (FIX knock-out) mouse received celiac injection of 11010pfu AdGTiIX or AdSPiIX. The highest expression level of hFIX in mouse plasma was 590 ng/mL and 690 ng/mL respectively, and the expression time lasted for 16 weeks and 9 weeks respectively. The bleeding time reduced from over 30 min to 7.5 min, and 5-min blood lost reduced from 430 mL to 60 mL. The results of anti-Ad IgG assays indicated that immune response triggered by AdGTiIX was obviously weaker than that triggered by AdSPiIX. These results indicated that, compared with previous adenovirus (pre-Ad), the mini-Ad vector sys-tem prolonged the expression time of hFIX and reduced immune response, thus offering a prom-ising result for further pre-clinical study.展开更多
Gene therapy provides a potential cure for hemophilia B, and significant progress has been achieved in liver-directed gene transfer mediated by adeno-associated viral vectors. Recent clinical trials involving the use ...Gene therapy provides a potential cure for hemophilia B, and significant progress has been achieved in liver-directed gene transfer mediated by adeno-associated viral vectors. Recent clinical trials involving the use of a self-complementary adeno-associated virus serotype 8-human codon-optimized factor IX （AAV8-hFIXco） vector demonstrated encouraging efficacy with hFIX expression stabilized at 1% to 6% of normal level in patients, but safety concerns related to high vector doses are still present. Thus, further improvement of AAV vectors and hFIX expression cassette may positively contribute to the ultimate success of hemophilia B gene therapy. In this study, to obtain a higher expression level of hFIX that potentiates the coagulant capacity of recipients, human FIX expression vector was optimized by upgrading the codon adaption index and adjusting the GC content, inserting a Kozak sequence （GCCACC）, and introducing a gain-of-function mutation, R338L （FIX Padua）. The efficiency of the published and the presently constructed cassettes was compared through in vivo screening. In addition, the regulatory elements that control the FIX gene expression in these cassettes were screened for liver-specific effectiveness. Among all the constructed cassettes, scAAV-Pre-hFIXco-SIH-R338L, which was the construct under the control of the prothrombin enhancer and prealbumin promoter, resulted in the highest level of coagulant activity, and the expression levels of two constructed cassettes （scAAV-Chi-hFIXco-SIH-R338L and scAAV-Pre- hFIXco-SIH-R338L） were also higher than that of the published cassette （scAAV-LPI-hFIXco-SJ）. In summary, our strategies led to a substantial increase in hFIX expression at the protein level or a remarkably elevated coagulant activity. Thus, these reconstructs of hFIX with AAV vector may potentially contribute to the creation of an efficacious gene therapy of hemophilia B.展开更多
Objective: To construct and apply a replacement targeting vector for mouse coagulation factor IX(mFIX) gene in embryonic stem (ES) cells. Methods: Based on the cloning and structural analysis of the genomic DNA fragme...Objective: To construct and apply a replacement targeting vector for mouse coagulation factor IX(mFIX) gene in embryonic stem (ES) cells. Methods: Based on the cloning and structural analysis of the genomic DNA fragment of coagulation factor IX gene from 129Sv mouse genomic DNA A phage library, PMFIXDEL plasmid was designed with positive-negative-selection (PNS) strategy, and constructed with commonmolecular cloning techniques. Structure of PMFIXDEL was identified by PCR and restriction analysis. Afterelectroporation with the linearized PMFIXDEL DNA, transfected ES cells were cultured in G418/GANC drugselection medium. The recombination efficacy of this vector was tested. Results: The main components ofPMFIXDEL were two copies of negative selection gene (HSV-tk expression cassette), a positive selectiongene (Neo expression cassette), long and short homologous fragments and plasmid backbone. The introduction of negative selection gene (HSV-tk ) into the construct resulted in 24-fold increase of selection.Conclusion: An effective replacement vector for mFIX gene targeting was constructed and applied in ES cell.展开更多
基金the High Technology Research and Development Programme of China and USA Grant ROIHL 39762
文摘DNA sequence of 2.2kb of factor IX gene from each of 27 cases of Hemophilia B patients living in Jiangsu, Hubei, Shandong, Guangdong, Fujian and Ningxia provinces was studied by using the PCR (Polymerase Chain Reaction) and GAWTS (Genomic Amplification with Transcript Sequencing) techniques. Twenty different mutations were found in 21 patients. Twelve of them were not reported before. Eight occured in CpG dinucleotide (38%) that was a hot spot of germ line mutations in Caucasian. No geographic specificity was found between 6 provinces. Six carriers were identified. Some advantages of the methodology were discussed.
基金the State High Technology Development Program (Grant No.Z20-02-01), Shanghai Post-doctoral Fellowship Foundation the National "863" High-Tech Program+1 种基金 the National Natural Science Foundation of China (Grant No. 39880019) Fok Ying Tung Foundation (Gra
文摘A mutant human factor IX with arginine at 338 residual changed to alanine (hFIXR338A) by site-directed mutagenesis was introduced into AAV vectors, and a recombinant adeno-associ- ated viral vector containing hFIXR338A, prepared by rHSV/AAV hybrid helper virus system, was directly introduced to the hind leg muscle of factor IX knock out mice. The expression and the biological activity of human factor IX mutant, hFIXR338A, and the immune response against it in the treated mice were assayed and detected. The results showed that (i) the high-level expression of human factor IX mutant protein, hFIXR338A, has been detected in rAAV-hFIXR338A treated hemophilia B mice and lasted more than 15 weeks; (ii) the clotting activity of hFIXR338A in plasma is 34.2%± 5.23%, which is remarkably higher than that of (14.27% ± 3.4%) of wild type hFIX treated mice in the activated partial thromboplastin assay; (iii) immune response against factor IX R338A was absent, with no factor IX mutant protein (hFIXR338A) inhibitors development in the treated mice; and (iv) no local or systemic side-effects and toxicity associated with the gene transfer were found. It demonstrated the potential use of treating hemophilia B by recombinant adeno-associated viral vectors with mutant hFIXR338A gene, an alternative strategy for hemophilia B gene therapy to wild-type human factor IX.
基金supported by the State High Technology Development Program(863).
文摘Vector GtiIX containing human clotting factor IX cDNA with intron 1 (hFIX mini-gene or Fi’IX) driven by CMV promoter was constructed based on the mini-adenoviral vector GT2073 (mini-Ad vector) with all viral protein coding sequences deleted. Mini-Ad packaging cell 293Cre4 was first transduced with GTiIX, and then was transfected with helper-adenovirus AdLC8, thus mini-Ad virions AdGTiIX were obtained. At the same time, previous normal adenoviral vector pAdSPiIX containing viral genome and hFIX mini-gene was constructed, and then previous ade-novirus (pre-Ad) AdSPiIX was obtained as control. The ratio of helper-adenovirus among purified virons AdGTiIX was less than 0.8%. 3T3 cells were transfected with AdGTiIX and AdSPiIX at a MOI of 50 per cell and ELISA result showed that transient expression level in vitro was 1.4±0.2 mg /106·24 h and 1.6±0.3 mg/106·24 h respectively. Each hemophilia B (FIX knock-out) mouse received celiac injection of 11010pfu AdGTiIX or AdSPiIX. The highest expression level of hFIX in mouse plasma was 590 ng/mL and 690 ng/mL respectively, and the expression time lasted for 16 weeks and 9 weeks respectively. The bleeding time reduced from over 30 min to 7.5 min, and 5-min blood lost reduced from 430 mL to 60 mL. The results of anti-Ad IgG assays indicated that immune response triggered by AdGTiIX was obviously weaker than that triggered by AdSPiIX. These results indicated that, compared with previous adenovirus (pre-Ad), the mini-Ad vector sys-tem prolonged the expression time of hFIX and reduced immune response, thus offering a prom-ising result for further pre-clinical study.
文摘Gene therapy provides a potential cure for hemophilia B, and significant progress has been achieved in liver-directed gene transfer mediated by adeno-associated viral vectors. Recent clinical trials involving the use of a self-complementary adeno-associated virus serotype 8-human codon-optimized factor IX （AAV8-hFIXco） vector demonstrated encouraging efficacy with hFIX expression stabilized at 1% to 6% of normal level in patients, but safety concerns related to high vector doses are still present. Thus, further improvement of AAV vectors and hFIX expression cassette may positively contribute to the ultimate success of hemophilia B gene therapy. In this study, to obtain a higher expression level of hFIX that potentiates the coagulant capacity of recipients, human FIX expression vector was optimized by upgrading the codon adaption index and adjusting the GC content, inserting a Kozak sequence （GCCACC）, and introducing a gain-of-function mutation, R338L （FIX Padua）. The efficiency of the published and the presently constructed cassettes was compared through in vivo screening. In addition, the regulatory elements that control the FIX gene expression in these cassettes were screened for liver-specific effectiveness. Among all the constructed cassettes, scAAV-Pre-hFIXco-SIH-R338L, which was the construct under the control of the prothrombin enhancer and prealbumin promoter, resulted in the highest level of coagulant activity, and the expression levels of two constructed cassettes （scAAV-Chi-hFIXco-SIH-R338L and scAAV-Pre- hFIXco-SIH-R338L） were also higher than that of the published cassette （scAAV-LPI-hFIXco-SJ）. In summary, our strategies led to a substantial increase in hFIX expression at the protein level or a remarkably elevated coagulant activity. Thus, these reconstructs of hFIX with AAV vector may potentially contribute to the creation of an efficacious gene therapy of hemophilia B.
文摘Objective: To construct and apply a replacement targeting vector for mouse coagulation factor IX(mFIX) gene in embryonic stem (ES) cells. Methods: Based on the cloning and structural analysis of the genomic DNA fragment of coagulation factor IX gene from 129Sv mouse genomic DNA A phage library, PMFIXDEL plasmid was designed with positive-negative-selection (PNS) strategy, and constructed with commonmolecular cloning techniques. Structure of PMFIXDEL was identified by PCR and restriction analysis. Afterelectroporation with the linearized PMFIXDEL DNA, transfected ES cells were cultured in G418/GANC drugselection medium. The recombination efficacy of this vector was tested. Results: The main components ofPMFIXDEL were two copies of negative selection gene (HSV-tk expression cassette), a positive selectiongene (Neo expression cassette), long and short homologous fragments and plasmid backbone. The introduction of negative selection gene (HSV-tk ) into the construct resulted in 24-fold increase of selection.Conclusion: An effective replacement vector for mFIX gene targeting was constructed and applied in ES cell.
