title: Inhibition of chromatin condensation prevents transgene silencing in a neural progenitor cell line transplanted to the rat brain.
abstract: The use of ex vivo gene therapy in the central nervous system has so far suffered from transgene downregulation. Condensation of the transgenic sequences has been proposed to be a mechanism involved in this silencing. In this study we inhibited either histone deacetylation or DNA methylation in neural progenitor cell lines, transduced with a lentiviral vector carrying green fluorescent protein (GFP), prior to grafting them into the rat striatum. The expression of GFP was significantly higher in grafts pretreated with either of the inhibitors. After 1 week in vivo we detected an 11-fold increase in the number of GFP-expressing cells due to the inhibition of DNA methylation in vitro with azadeoxycytidine and a ninefold increase when inhibiting histone deacetylation with trichostatin A. This suggests that a pretreatment paradigm could be used to increase efficacy of ex vivo delivery of a therapeutic protein locally in the brain.
authors.affiliation: Wallenberg Neuroscience Center, Department of Physiological Sciences, Division of Neurobiology, Lund University, Lund, Sweden.
authors.forename: Nina
authors.initials: N
authors.lastname: Rosenqvist
authors.forename: Johan
authors.initials: J
authors.lastname: Jakobsson
authors.forename: Cecilia
authors.initials: C
authors.lastname: Lundberg
mesh_terms: D000818:Animals; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D001921:Brain / Q000166:cytology / Q000502:physiology*; D016380:Brain Tissue Transplantation; D002461:Cell Line, Transformed; D042002:Chromatin Assembly and Disassembly / Q000187:drug effects / Q000502:physiology*; D000077209:Decitabine; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D020868:Gene Silencing / Q000187:drug effects / Q000502:physiology*; D006570:Heterochromatin / Q000378:metabolism; D006877:Hydroxamic Acids / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*; D019076:Transgenes / Q000502:physiology*
chemical_list: D004791:Enzyme Inhibitors; D006570:Heterochromatin; D006877:Hydroxamic Acids; C012589:trichostatin A; D000077209:Decitabine; D001374:Azacitidine