Polylysine Modification of Adenoviral Fiber Protein Enhances Muscle Cell Transduction

Abstract

Adenoviral vectors (ADVs) are used widely for gene delivery to different tissues including muscle. One particularly promising use for ADVs is in the transfer of the dystrophin gene to the muscle of patients with Duchenne muscular dystrophy (DMD). However, studies in different animal models of DMD suggest that ADVs inefficiently transduce mature skeletal muscle. In this article we test whether AdZ.F(pK7), a genetically modified ADV that expresses a polylysine moiety on the end of the fiber protein, could enhance transduction of muscle cells and circumvent the maturation-dependent loss of muscle infectivity by ADVs. The efficiency of transduction was tested at different levels of muscle maturation. In vitro, AdZ.F(pK7) showed a higher level of transduction at all stages of differentiation including myoblasts, myotubes, and single muscle fibers. In vivo, mature skeletal muscle was transduced fourfold better by AdZ.F(pK7) than by the unmodifled vector (AdZ.F). Together, these observations demonstrate improved ADV transduction of skeletal muscle by modifying ADV tropism, and provide a proof-of-principle that modification of ADVs to target muscle-specific molecules could result in tissue-specific transfer of skeletal muscle tissue as well.

Fiber-Modified Adenovirus Vectors Decrease Liver Toxicity through Reduced IL-6 Production

“…Expanded and efficient gene transfer has been reported based on the use of mutant fiber proteins containing a stretch of lysine residues (23)(24)(25). However, there has been no report on the difference in gene transfer activity and toxicity in vivo between the conventional Ad vector and the fibermodified Ad vector containing the K7 peptide.…”

“…We found that the fiber-modified Ad vector containing a stretch of lysine residues (K7 (KKKKKKK) peptide) (23)(24)(25) that target heparan sulfates on the cellular surface greatly reduced IL-6 and liver toxicity after i.v. injection into mice compared with the conventional Ad vector.…”

Comparison of high-capacity and first-generation adenoviral vector gene delivery to murine muscle in utero

“…bgal activity and protein concentration were measured as described previously. 11,22 Concurrently measured background bgal activity levels in uninjected muscle extracts are subtracted from all sample values.…”

Influence of adenoviral fiber mutations on viral encapsidation, infectivity and in vivo tropism

“…The selected ligand is a peptide composed of seven lysine residues (7K) which is known to confer to the modified virus the ability to efficiently bind heparan sulfate-containing glycoproteins on the surface of target cells. [27][28][29][30] The growth characteristics of viruses carrying or not carrying the additional ligand have been compared using heparan sulfate-containing 293 cells (Figure 5a). We thus demonstrated that the Ad/Fb-Ser408Glu-7K virus propagates as efficiently as the wild-type virus on 293 cells while the kinetic growth of the Ad-LacZ/Fb-Ser408Glu was significantly reduced (Figure 5a).…”