title: Glucocorticoid-inducible retrovector for regulated transgene expression in genetically engineered bone marrow stromal cells.
abstract: Transplantable bone marrow stromal cells can be utilized for cell therapy of mesenchymal disorders. They can also be genetically engineered to express synthetic transgenes and subsequently serve as a platform for systemic delivery of therapeutic proteins in vivo. Inducible production of therapeutic proteins would markedly enhance the usefulness of stromal cells for cell therapy applications. We determined whether synthetic corticosteroid hormones can be used to tightly control transgene expression via the glucocorticoid response pathway in primary bone marrow stromal cells. This regulatory mechanism does not require the presence of potentially immunogenic prokaryotic or chimeric "Trans-activators." Further, synthetic corticosteroids are pharmaceutical agents that can be readily used in vivo. We designed a self-inactivating retroviral vector in which expression of the green fluorescent protein (GFP) reporter is controlled by a minimal synthetic promoter composed of five tandem glucocorticoid response elements upstream of a TATAA box. Vesicular stomatitis virus G-pseudotyped retroparticles were synthesized and utilized to transduce cultured cell lines and primary rat bone marrow stromal cells. We have shown that primary rat bone marrow stromal cells could be efficiently engineered with our GRE-containing retrovector, basal reporter expression was low in the absence of exogenous synthetic corticosteroids, and GFP expression was dexamethasone inducible and reversible. To summarize, this strategy allows dexamethasone-induced, "on-demand" transgene expression from transplantable genetically engineered bone marrow stromal cells.
authors.affiliation: Department of Medicine, Lady Davis Institute for Medical Research, McGill University, Montreal, Canada.
authors.forename: D E
authors.initials: DE
authors.lastname: Jaalouk
authors.forename: N
authors.initials: N
authors.lastname: Eliopoulos
authors.forename: C
authors.initials: C
authors.lastname: Couture
authors.forename: S
authors.initials: S
authors.lastname: Mader
authors.forename: J
authors.initials: J
authors.lastname: Galipeau
mesh_terms: D000818:Animals; D001483:Base Sequence; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D005818:Genetic Engineering / Q000379:methods*; D005822:Genetic Vectors / Q000235:genetics; D005938:Glucocorticoids / Q000494:pharmacology*; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006801:Humans; D008164:Luminescent Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D051381:Rats; D011917:Rats, Inbred Lew; D020218:Response Elements / Q000235:genetics; D012190:Retroviridae / Q000235:genetics*; D017154:Stromal Cells / Q000187:drug effects / Q000502:physiology; D019076:Transgenes
chemical_list: D005938:Glucocorticoids; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins; D003907:Dexamethasone