UCLA

Insulators can be used to increase the therapeutic potential of gene therapy for sickle cell disease (SCD) by improving safety and resisting transgene silencing. Four experimental lentiviral vectors (LVs) carrying the betaAS3 transgene were engineered to contain the FB and Ank small insulator elements. When evaluated in single vector copy MEL cell clones, the Ank R LV demonstrated barrier activity that most closely resembled that observed with the positive control 1.2kb cHS4 insulator. Erythrocytes derived from human SCD hematopoietic stem/progenitor cells (HSPCs) transduced with the Ank R LV did not yield higher betaAS3 expression or phenotypic correction of the sickle shape than levels produced without a barrier insulator. Since the benefits of the Ank insulator in the betaAS3 LV are yet to be realized in primary cells, future experiments using serial transplants of murine HSPCs are needed to determine the extent of the barrier activity in the Ank R LV.