title: Endogenous microRNA can be broadly exploited to regulate transgene expression according to tissue, lineage and differentiation state.
abstract: We have shown previously that transgene expression can be suppressed in hematopoietic cells using vectors that are responsive to microRNA (miRNA) regulation. Here we investigate the potential of this approach for more sophisticated control of transgene expression. Analysis of the relationship between miRNA expression levels and target mRNA suppression suggested that suppression depends on a threshold miRNA concentration. Using this information, we generated vectors that rapidly adjust transgene expression in response to changes in miRNA expression. These vectors sharply segregated transgene expression between closely related states of therapeutically relevant cells, including dendritic cells, hematopoietic and embryonic stem cells, and their progeny, allowing positive/negative selection according to the cells' differentiation state. Moreover, two miRNA target sites were combined to restrict transgene expression to a specific cell type in the liver. Notably, the vectors did not detectably perturb endogenous miRNA expression or regulation of natural targets. The properties of miRNA-regulated vectors should allow for safer and more effective therapeutic applications.
authors.affiliation: San Raffaele Telethon Institute for Gene Therapy, San Raffaele Scientific Institute, via Olgettina, 58, 20132 Milan, Italy.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Brown
authors.forename: Bernhard
authors.initials: B
authors.lastname: Gentner
authors.forename: Alessio
authors.initials: A
authors.lastname: Cantore
authors.forename: Silvia
authors.initials: S
authors.lastname: Colleoni
authors.forename: Mario
authors.initials: M
authors.lastname: Amendola
authors.forename: Anna
authors.initials: A
authors.lastname: Zingale
authors.forename: Alessia
authors.initials: A
authors.lastname: Baccarini
authors.forename: Giovanna
authors.initials: G
authors.lastname: Lazzari
authors.forename: Cesare
authors.initials: C
authors.lastname: Galli
authors.forename: Luigi
authors.initials: L
authors.lastname: Naldini
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D020868:Gene Silencing / Q000502:physiology*; D018390:Gene Targeting / Q000379:methods*; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D013234:Stem Cells / Q000166:cytology* / Q000502:physiology*; D019076:Transgenes / Q000235:genetics*
chemical_list: D035683:MicroRNAs