AAV-mediated gene transfer to skeletal muscle

Area of Science:

• Biotechnology
• Gene Therapy
• Viral Vector Technology

Background:

• Adeno-associated viral (AAV) vectors are derived from a nonpathogenic, replication-deficient virus.
• AAV vectors possess a small single-stranded DNA genome and are devoid of viral-coding sequences.
• They efficiently transduce nondividing cells like muscle fibers and hepatocytes in vivo.

Purpose of the Study:

• To evaluate the safety and efficacy of adeno-associated viral (AAV) vectors for gene transfer.
• To demonstrate sustained expression of therapeutic transgenes using AAV vectors.
• To assess the potential of AAV vectors in correcting genetic disease phenotypes in animal models.

Main Methods:

• Administration of recombinant AAV to skeletal muscle in experimental animals and humans.
• Intramuscular (im) injection of AAV vectors in various species including mice, hamsters, dogs, and nonhuman primates.
• Monitoring for local or systemic toxicity and assessing transgene expression levels.

Main Results:

• Recombinant AAV administered at high doses showed no local or systemic toxicity in humans and animals.
• Reduced potential for activating cytotoxic T lymphocytes compared to other viral vectors, minimizing inflammation.
• Sustained expression of therapeutic transgenes (e.g., F.IX, erythropoietin, IGF) demonstrated in vivo.
• Efficient gene transfer to myofibers achieved via intramuscular injection across multiple species.
• Correction of disease phenotypes observed in animal models of hemophilia B, muscular dystrophy, and beta-thalassemia.

Conclusions:

• AAV vectors are safe and effective tools for gene therapy, exhibiting low immunogenicity.
• Efficient gene transfer and sustained therapeutic transgene expression can be achieved in nondividing cells.
• AAV-mediated gene therapy holds significant promise for treating a range of genetic disorders.