Computationally designed liver-specific transcriptional modules and hyperactive factor IX improve hepatic gene therapy

The development of the next-generation gene therapy vectors for hemophilia requires using lower and thus potentially safer vector doses and augmenting their therapeutic efficacy. We have identified hepatocyte-specific transcriptional cis-regulatory modules (CRMs) by using a computational strategy that increased factor IX (FIX) levels 11- to 15-fold. Vector efficacy could be enhanced by combining these hepatocyte-specific CRMs with a synthetic codon-optimized hyperfunctional FIX-R338L Padua transgene. This Padua mutation boosted FIX activity up to sevenfold, with no apparent increase in thrombotic risk. We then validated this combination approach using self-complementary adenoassociated virus serotype 9 (scAAV9) vectors in hemophilia B mice. This resulted in sustained supraphysiologic FIX activity (400%), correction of the bleeding diathesis at clinically relevant, low vector doses (5 × 10(10) vector genomes [vg]/kg) that are considered safe in patients undergoing gene therapy. Moreover, immune tolerance could be induced that precluded induction of inhibitory antibodies to FIX upon immunization with recombinant FIX protein.

Publication year:2014

BOF-keylabel:yes

IOF-keylabel:yes

BOF-publication weight:10

CSS-citation score:2

Authors:International

Authors from:Higher Education