MiRNA Lentiviral Vector Integration and Gene Targeting Efficacy in Cardiac Progenitors

Abstract

Stem and progenitor cardiac cells are challenging for possible cell therapy application. Several research laboratories are exploiting the feasibility of autologous cell therapy approach to get rid of immunosuppressive treatments responsible for undesirable side effects. Recently, we showed that cardiac progenitors isolated from Sgcb null mice, animal model of limb-girdle muscular dystrophy type 2E, undergo an aberrant differentiation in vitro and in vivo due to the dysregulation of miR669. This miRNA family is able to inhibit the skeletal myogenic program directly targeting MyoD 3’ UTR. Using lentiviral technology we provided evidence that it is possible to rescue the dystrophic aberrant phenotype by miRNA669overexpression without gene correction. However, how the viruses carrying the miRNAs were positioned in the genome upon transduction and how their localization site could influence the rescue potential was not analysed. Here we investigate the integration profile of lentiviral vector carrying the pre-miR669 in infected polyclonal and clonal populations derived from Sgcb cardiac progenitors. Our study reveals that the retroviral insertion sites (RIS) are largely restricted to coding genes (65%). Although with the limitation of our analysis, we found no hits for cancer-related genes and several sequenced RIS brought to light genes mainly involved in muscle function. Thus our data show that lentiviral vector insertional profile is cell-specific, however, the chromatin state of target cells positively influences the viral integrations.