Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019045 (hemoglobinopathies)
 2,704 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have examined whether the secretion of erythropoietin (Epo) from genetically modified cells could represent an alternative to repeated injections of the recombinant hormone for treating chronic anemias responsive to Epo. Primary mouse skin fibroblasts were transduced with a retroviral vector in which the murine Epo cDNA is expressed under the control of the murine phosphoglycerate kinase promoter. "Neo-organs" containing the genetically modified fibroblasts embedded into collagen lattices were implanted into the peritoneal cavity of mice. Increased hematocrit (> 80%) and elevated serum Epo concentration (ranging from 60 to 408 milliunits/ml) were observed in recipient animals over a 10-month observation period. Hematocrit values measured in recipient mice varied according to the number of implanted Epo-secreting fibroblasts (ranging from 2.5 to 20 x 10(6)). The implantation of neo-organs containing Epo-secreting fibroblasts appeared, therefore, as a convenient method to achieve permanent in vivo delivery of the hormone. We estimated that the biological efficacy of the approach may be relevant for the treatment of human hemoglobinopathies.
 ...
PMID:Sustained delivery of erythropoietin in mice by genetically modified skin fibroblasts. 772 39

Transcriptional silencing of genes transferred into hematopoietic stem cells poses one of the most significant challenges to the success of gene therapy. If the transferred gene is not completely silenced, a progressive decline in gene expression as the mice age often is encountered. These phenomena were observed to various degrees in mouse transplant experiments using retroviral vectors containing a human beta-globin gene, even when cis-linked to locus control region derivatives. Here, we have investigated whether ex vivo preselection of retrovirally transduced stem cells on the basis of expression of the green fluorescent protein driven by the CpG island phosphoglycerate kinase promoter can ensure subsequent long-term expression of a cis-linked beta-globin gene in the erythroid lineage of transplanted mice. We observed that 100% of mice (n = 7) engrafted with preselected cells concurrently expressed human beta-globin and the green fluorescent protein in 20-95% of their RBC for up to 9.5 mo posttransplantation, the longest time point assessed. This expression pattern was successfully transferred to secondary transplant recipients. In the presence of beta-locus control region hypersensitive site 2 alone, human beta-globin mRNA expression levels ranged from 0.15% to 20% with human beta-globin chains detected by HPLC. Neither the proportion of positive blood cells nor the average expression levels declined with time in transplanted recipients. Although suboptimal expression levels and heterocellular position effects persisted, in vivo stem cell gene silencing and age-dependent extinction of expression were avoided. These findings support the further investigation of this type of vector for the gene therapy of human hemoglobinopathies.
 ...
PMID:Preselection of retrovirally transduced bone marrow avoids subsequent stem cell gene silencing and age-dependent extinction of expression of human beta-globin in engrafted mice. 1080 62