Linked Life Data

9787090

Source:http://linkedlifedata.com/resource/pubmed/id/9787090

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1998-11-25
pubmed:abstractText
Congenital erythropoietic porphyria (CEP) is an autosomal recessive disorder resulting from the deficient activity of the heme biosynthetic enzyme uroporphyrinogen III synthase (UROS). Severely affected patients are transfusion dependent and have mutilating cutaneous manifestations. Successful bone marrow transplantation has proven curative, providing the rationale for stem cell gene therapy. Toward this goal, two retroviral MFG vectors containing the UROS cDNA were constructed, one with the wild-type sequence (MFG-UROS-wt) and a second with an optimized Kozak consensus sequence (MFG-UROS-K). Following transduction of CEP fibroblasts, the MFG-UROS-wt and MFG-UROS-K vectors increased the endogenous activity without selection to levels that were 18- and 5-fold greater, respectively, than the mean activity in normal fibroblasts. Notably, the MFG-UROS-wt vector expressed UROS activity in CEP fibroblasts at these high levels for over 6 months without cell toxicity. Addition of either delta-aminolevulinic acid (ALA) or ferric chloride did not affect expression of the transduced UROS gene nor did the increased concentrations of uroporphyrin isomers or porphyrin intermediates affect cell viability. Similarly, transduction of CEP lymphoblasts with the MFG-UROS-wt vector without G418 selection increased the endogenous UROS activity by 7-fold or almost 2-fold greater than that in normal lymphoblasts. Transduction of K562 erythroleukemia cells by cocultivation with the MFG-UROS-wt producer cells increased their high endogenous UROS activity by 1.6-fold without selection. Clonally isolated K562 cells expressed UROS for over 4 months at mean levels 4.7-fold greater than the endogenous activity without cell toxicity. Thus, the prolonged, high-level expression of UROS in transduced CEP fibroblasts and lymphoblasts, as well as in transduced K562 erythroid cells, demonstrated that the enzymatic defect in CEP cells could be corrected by retroviral-mediated gene therapy without selection and that the increased intracellular porphyrin intermediates were not toxic to these cells, even when porphyrin production was stimulated by supplemental ALA or iron. These in vitro studies provide the rationale for ex vivo stem cell gene therapy in severely affected patients with CEP.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1096-7192
pubmed:author
pubmed:copyrightInfo
Copyright 1998 Academic Press.
pubmed:issnType
Print
pubmed:volume
65
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10-7
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Congenital erythropoietic porphyria: prolonged high-level expression and correction of the heme biosynthetic defect by retroviral-mediated gene transfer into porphyric and erythroid cells.
pubmed:affiliation
Department of Human Genetics, Mount Sinai School of Medicine, New York, New York 10029, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.