Project description:The two obstacles that impede a wider application of genetically modified cells expressing therapeutic transgenes for ex vivo gene therapy are the immune mediated rejection of the transplanted cells, combined with their potential to cause iatrogenic oncogenesis. In this study we describe a new cellular vehicle for this form of therapy,; termed the cord lining epithelial cell (CLEC). CLECs are derived from the human amnion and incorporate many of the immunoregulatory functions associated with the fetal/maternal interface. We show that CLECs can be safely transfected by phage ÏC31 integrase to accomplish site-specific integration of a therapeutic human transgene. We also show that transplanted CLECs are not oncogenic in vivo and can be maintained in immunocompetent mice where acute xeno-rejection rapidly destroys other human cell types. Finally, we demonstrate the utility of CLECs for ex vivo gene therapy by delivering human coagulation factor 8 to mice with Hemophilia A. Experiment Overall Design: The transcriptome datasets of human umbilical cord lining epithelial cells were compared before(CLEC) and 1 month after(CLEC-GFP) phage integrase mediated integration of EGFP cDNA into the genome. Transcriptome datasets were generated in singles and genes differentiallty expressed in cells before and after phage integrase treatment were analysed. Genes differentially expressed by at least 2 fold as compared to untreated CLEC were considered to be significantly dysregulated. List of genes with significant dysregulation were used for further analysis and to used to determine if genomic integration events had resulted in any potential geno-toxicity.
Project description:The two obstacles that impede a wider application of genetically modified cells expressing therapeutic transgenes for ex vivo gene therapy are the immune mediated rejection of the transplanted cells, combined with their potential to cause iatrogenic oncogenesis. In this study we describe a new cellular vehicle for this form of therapy, termed the cord lining epithelial cell (CLEC). CLECs are derived from the human amnion and incorporate many of the immunoregulatory functions associated with the fetal/maternal interface. We show that CLECs can be safely transfected by phage φC31 integrase to accomplish site-specific integration of a therapeutic human transgene. We also show that transplanted CLECs are not oncogenic in vivo and can be maintained in immunocompetent mice where acute xeno-rejection rapidly destroys other human cell types. Finally, we demonstrate the utility of CLECs for ex vivo gene therapy by delivering human coagulation factor 8 to mice with Hemophilia A. High-resolution copy number profiling was performed on genomic DNA of untreated (GSM315546 and GSM315713) and phage integrase modified CLECs (GSM315974 and GSM316895) using the Human Mapping 500K Array Set (Affymetrix) and the data analyzed using GeneChip Chromosome Copy Number Analysis Tool. Regions of copy number gain or loss were defined as having 3 consecutive SNPs concordant for significant copy number abnormalities. Log2 signal intensity ratios >0.3 and <-0.3 were criteria for significant copy number gain and loss, respectively.
Project description:The two obstacles that impede a wider application of genetically modified cells expressing therapeutic transgenes for ex vivo gene therapy are the immune mediated rejection of the transplanted cells, combined with their potential to cause iatrogenic oncogenesis. In this study we describe a new cellular vehicle for this form of therapy, termed the cord lining epithelial cell (CLEC). CLECs are derived from the human amnion and incorporate many of the immunoregulatory functions associated with the fetal/maternal interface. We show that CLECs can be safely transfected by phage φC31 integrase to accomplish site-specific integration of a therapeutic human transgene. We also show that transplanted CLECs are not oncogenic in vivo and can be maintained in immunocompetent mice where acute xeno-rejection rapidly destroys other human cell types. Finally, we demonstrate the utility of CLECs for ex vivo gene therapy by delivering human coagulation factor 8 to mice with Hemophilia A.
Project description:The two obstacles that impede a wider application of genetically modified cells expressing therapeutic transgenes for ex vivo gene therapy are the immune mediated rejection of the transplanted cells, combined with their potential to cause iatrogenic oncogenesis. In this study we describe a new cellular vehicle for this form of therapy, termed the cord lining epithelial cell (CLEC). CLECs are derived from the human amnion and incorporate many of the immunoregulatory functions associated with the fetal/maternal interface. We show that CLECs can be safely transfected by phage φC31 integrase to accomplish site-specific integration of a therapeutic human transgene. We also show that transplanted CLECs are not oncogenic in vivo and can be maintained in immunocompetent mice where acute xeno-rejection rapidly destroys other human cell types. Finally, we demonstrate the utility of CLECs for ex vivo gene therapy by delivering human coagulation factor 8 to mice with Hemophilia A.
Project description:The Gypsy-like element Ty3 inserts proximal to the transcription start sites of genes transcribed by RNA polymerase 3 (RNAP3). In this study, a random-barcode Ty3 was used to count Ty3 insertions at specific sites. Surprisingly, saturation transposition of the yeast genome showed that tDNAs even within isoacceptor families are targeted at widely different frequencies. Ectopic expression of Ty3 integrase showed that it localizes to integration targets independent of other Ty3 proteins. Binding of integrase, RNAP3 and factor Brf1 at individual targets did not differ to the same extent as integration. Metadata analysis showed that histone modification H3K4Ac correlated positively with insertion frequency. Targeting frequency could be reconstituted on high copy plasmids containing only 75 bp of 5’ flanking sequence plus the tDNA target. Weighting of insertions according to frequency identified an A/T-rich sequence followed by C as the site of gene-proximal strand transfer. This site lies immediately adjacent to the adenines of the RNAP3 transcription start site motif (CAA). Recent structures of DNA in RNAP3 initiation complexes show that in the initiation complex the transcription start site is sharply bent at the position adjacent to the gene-proximal Ty3 strand transfer. We propose that Ty3 integration occurs in two steps: in the first, host Brf1 engages integrase; in the second, integrase exploits YR flexibility, and that together, these steps determine the wide range of Ty3 targeting frequencies.
Project description:The Gypsy-like element Ty3 inserts proximal to the transcription start sites of genes transcribed by RNA polymerase 3 (RNAP3). In this study, a random-barcode Ty3 was used to count Ty3 insertions at specific sites. Surprisingly, saturation transposition of the yeast genome showed that tDNAs even within isoacceptor families are targeted at widely different frequencies. Ectopic expression of Ty3 integrase showed that it localizes to integration targets independent of other Ty3 proteins. Binding of integrase, RNAP3 and factor Brf1 at individual targets did not differ to the same extent as integration. Metadata analysis showed that histone modification H3K4Ac correlated positively with insertion frequency. Targeting frequency could be reconstituted on high copy plasmids containing only 75 bp of 5’ flanking sequence plus the tDNA target. Weighting of insertions according to frequency identified an A/T-rich sequence followed by C as the site of gene-proximal strand transfer. This site lies immediately adjacent to the adenines of the RNAP3 transcription start site motif (CAA). Recent structures of DNA in RNAP3 initiation complexes show that in the initiation complex the transcription start site is sharply bent at the position adjacent to the gene-proximal Ty3 strand transfer. We propose that Ty3 integration occurs in two steps: in the first, host Brf1 engages integrase; in the second, integrase exploits YR flexibility, and that together, these steps determine the wide range of Ty3 targeting frequencies.
Project description:The Gypsy-like element Ty3 inserts proximal to the transcription start sites of genes transcribed by RNA polymerase 3 (RNAP3). In this study, a random-barcode Ty3 was used to count Ty3 insertions at specific sites. Surprisingly, saturation transposition of the yeast genome showed that tDNAs even within isoacceptor families are targeted at widely different frequencies. Ectopic expression of Ty3 integrase showed that it localizes to integration targets independent of other Ty3 proteins. Binding of integrase, RNAP3 and factor Brf1 at individual targets did not differ to the same extent as integration. Metadata analysis showed that histone modification H3K4Ac correlated positively with insertion frequency. Targeting frequency could be reconstituted on high copy plasmids containing only 75 bp of 5’ flanking sequence plus the tDNA target. Weighting of insertions according to frequency identified an A/T-rich sequence followed by C as the site of gene-proximal strand transfer. This site lies immediately adjacent to the adenines of the RNAP3 transcription start site motif (CAA). Recent structures of DNA in RNAP3 initiation complexes show that in the initiation complex the transcription start site is sharply bent at the position adjacent to the gene-proximal Ty3 strand transfer. We propose that Ty3 integration occurs in two steps: in the first, host Brf1 engages integrase; in the second, integrase exploits YR flexibility, and that together, these steps determine the wide range of Ty3 targeting frequencies.
Project description:This SuperSeries is composed of the following subset Series: GSE22544: Integration of transcript expression, copy number and LOH analysis of infiltrating ductal carcinoma of the breast: expression analysis GSE22839: Integration of transcript expression, copy number and LOH analysis of infiltrating ductal carcinoma of the breast: copy number analysis Refer to individual Series