title: Dynamics of transgene expression in a neural stem cell line transduced with lentiviral vectors incorporating the cHS4 insulator.
abstract: Transplantation of genetically manipulated cells to the central nervous system holds great promise for the treatment of several severe neurological disorders. The success of this strategy relies on sufficient levels of transgene expression after transplantation. This has been difficult to achieve, however, due to transgene silencing. In this study, we transduced the neural stem cell line RN33B with self-inactivating lentiviral vectors and analyzed transgenic expression of green fluorescent protein (GFP) in several different settings both in vitro and after transplantation to the brain. We found that the transgene was affected of silencing both when transduced cells were proliferating and after differentiation. To prevent silencing, the cHS4 insulator was incorporated into the lentiviral vector. We found that a vector carrying the cHS4 insulator was partially protected against differentiation-dependent downregulation in vitro and in vivo. However, in proliferating cells, we found evidence for variegation and positional effects that were not prevented by the cHS4 insulator, suggesting that the mechanism behind silencing in proliferating cells is not the same mechanism influencing differentiation-dependent silencing. Taken together, these findings favor vector optimization as a strategy for achieving efficient ex vivo gene transfer in the central nervous system.
authors.affiliation: Wallenberg Neuroscience Center, Department of Physiological Sciences, Lund University, S-221 84, Lund, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Jakobsson
authors.forename: Nina
authors.initials: N
authors.lastname: Rosenqvist
authors.forename: Lachlan
authors.initials: L
authors.lastname: Thompson
authors.forename: Perrine
authors.initials: P
authors.lastname: Barraud
authors.forename: Cecilia
authors.initials: C
authors.lastname: Lundberg
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D002455:Cell Division / Q000235:genetics; D002460:Cell Line; D002645:Chickens; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D020868:Gene Silencing / Q000502:physiology; D018014:Gene Transfer Techniques / Q000639:trends*; D005822:Genetic Vectors / Q000235:genetics*; D049452:Green Fluorescent Proteins; D006801:Humans; D038101:Insulator Elements / Q000235:genetics*; D016086:Lentivirus / Q000235:genetics*; D008164:Luminescent Proteins / Q000235:genetics; D009474:Neurons / Q000166:cytology / Q000378:metabolism / Q000637:transplantation; D051381:Rats; D033581:Stem Cell Transplantation / Q000379:methods / Q000639:trends; D014161:Transduction, Genetic / Q000379:methods; D014162:Transfection / Q000379:methods / Q000639:trends; D019076:Transgenes / Q000235:genetics*
chemical_list: D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins