Abstract:
Nucleic acids are an emerging class of therapeutics with the capacity to repair
both DNA and RNA mutations in clinically relevant targets. We have used two
approaches, mobile group II introns and Spliceosome Mediated RNA Trans-splicing
(SMaRT), to correct β-globin mutations at the DNA and RNA levels respectively. We
show that the group II intron inserts site-specifically into its DNA target, even when
similar targets are available. Experiments transitioning this therapeutic into mammalian
cell systems are then described. We also illustrate how SMaRT RNA repair can be used
to correct β-globin mutations involved in sickle cell disease and some forms of β-
thalassemia. We uncovered diverse repair efficiencies when targeting sickle cell versus β-
thalassemia transcripts in mammalian cells. Possible reasons for this and how it might
direct target choice for the SMaRT therapeutic approach are both discussed. The
therapeutic molecule in SMaRT, a Pre-Trans-splicing Molecule or PTM, is also delivered
via lentivirus to erythrocyte precursors cultured from the peripheral blood of sickle cell
patients. Preliminary results from these experiments are discussed.
