title: Terminal differentiation of cardiac and skeletal myocytes induces permissivity to AAV transduction by relieving inhibition imposed by DNA damage response proteins.
abstract: Gene therapy vectors based on the adeno-associated virus (AAV) are extremely efficient for gene transfer into post-mitotic cells of heart, muscle, brain, and retina. The reason for their exquisite tropism for these cells has long remained elusive. Here, we show that upon terminal differentiation, cardiac and skeletal myocytes downregulate proteins of the DNA damage response (DDR) and that this markedly induces permissivity to AAV transduction. We observed that expression of members of the MRN complex (Mre11, Rad50, Nbs1), which bind the incoming AAV genomes, faded in cardiomyocytes at ~2 weeks after birth, as well as upon myoblast differentiation in vitro; in both cases, withdrawal of the cells from the cell cycle coincided with increased AAV permissivity. Treatment of proliferating cells with short-interfering RNAs (siRNAs) against the MRN proteins, or with microRNA-24, which is normally upregulated upon terminal differentiation and negatively controls the Nbs1 levels, significantly increased permissivity to AAV transduction. Consistently, delivery of these small RNAs to the juvenile liver concomitant with AAV markedly improved in vivo hepatocyte transduction. Collectively, these findings support the conclusion that cellular DDR proteins inhibit AAV transduction and that terminal cell differentiation relieves this restriction.
authors: Molecular Medicine Laboratory, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy.
authors: Jasmina
authors: J
authors: Lovric
authors: Miguel
authors: M
authors: Mano
authors: Lorena
authors: L
authors: Zentilin
authors: Ana
authors: A
authors: Eulalio
authors: Serena
authors: S
authors: Zacchigna
authors: Mauro
authors: M
authors: Giacca
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D017766:Acid Anhydride Hydrolases; D000818:Animals; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation; D049109:Cell Proliferation; D004249:DNA Damage; D045643:DNA Repair Enzymes / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D000229:Dependovirus / Q000235:genetics*; D015536:Down-Regulation; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006321:Heart / Q000254:growth & development; D006801:Humans; D008099:Liver / Q000378:metabolism / Q000821:virology; D000076228:MRE11 Homologue Protein; D051379:Mice; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D018485:Muscle Fibers, Skeletal / Q000502:physiology* / Q000821:virology; D032383:Myocytes, Cardiac / Q000502:physiology* / Q000821:virology; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D014161:Transduction, Genetic; D001616:beta-Galactosidase / Q000096:biosynthesis / Q000235:genetics
chemical_list: D018528:ATP-Binding Cassette Transporters; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D035683:MicroRNAs; C529080:Mirn24 microRNA, mouse; C512689:Mre11a protein, mouse; C466108:Nijmegen breakage syndrome 1 protein, mouse; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; D000076228:MRE11 Homologue Protein; D001616:beta-Galactosidase; D017766:Acid Anhydride Hydrolases; C495198:Rad50 protein, mouse; D045643:DNA Repair Enzymes