title: A microRNA-regulated lentiviral vector mediates stable correction of hemophilia B mice.
abstract: A longstanding goal for the treatment of hemophilia B is the development of a gene transfer strategy that can maintain sustained production of clotting factor IX (F.IX) in the absence of an immune response. To this end, we have sought to use lentiviral vectors (LVs) as a means for systemic gene transfer. Unfortunately, initial evaluation of LVs expressing F.IX from hepatocyte-specific promoters failed to achieve sustained F.IX expression in hemophilia B mice due to the induction of an anti-F.IX cellular immune response. Further analysis suggested that this may be a result of off-target transgene expression in hematopoietic-lineage cells of the spleen. In order to overcome this problem, we modified our vector to contain a target sequence for the hematopoietic-specific microRNA, miR-142-3p. This eliminated off-target expression in hematopoietic cells, and enabled sustained gene transfer in hemophilia B mice for more than 280 days after injection. Treated mice had more than 10% normal F.IX activity, no detectable anti-F.IX antibodies, and were unresponsive to F.IX immunization. Importantly, the mice survived tail-clip challenge, thus demonstrating phenotypic correction of their bleeding diathesis. This work, which is among the first applications to exploit the microRNA regulatory pathway, provides the basis for a promising new therapy for the treatment of hemophilia B.
authors.affiliation: San Raffaele Telethon Institute for Gene Therapy, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Brown
authors.forename: Alessio
authors.initials: A
authors.lastname: Cantore
authors.forename: Andrea
authors.initials: A
authors.lastname: Annoni
authors.forename: Lucia Sergi
authors.initials: LS
authors.lastname: Sergi
authors.forename: Angelo
authors.initials: A
authors.lastname: Lombardo
authors.forename: Patrizia
authors.initials: P
authors.lastname: Della Valle
authors.forename: Armando
authors.initials: A
authors.lastname: D'Angelo
authors.forename: Luigi
authors.initials: L
authors.lastname: Naldini
mesh_terms: D000818:Animals; D000906:Antibodies; D001773:Blood Cells / Q000378:metabolism; D005164:Factor IX / Q000008:administration & dosage / Q000276:immunology; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000627:therapeutic use*; D002836:Hemophilia B / Q000628:therapy*; D016086:Lentivirus / Q000235:genetics*; D051379:Mice; D035683:MicroRNAs / Q000235:genetics / Q000494:pharmacology*
chemical_list: D000906:Antibodies; D035683:MicroRNAs; D005164:Factor IX