Genome-Wide Characterization of Recombinant AAV6 Vector Integration in Human CD34^＋ Cells

Area of Science:

• Gene Therapy
• Virology
• Genomics

Background:

• Viral vectors are crucial for gene therapy but raise safety concerns due to genome integration.
• Recombinant adeno-associated virus serotype 6 (rAAV6) is a promising non-pathogenic vector for hematopoietic stem cell therapy.
• The chromosomal integration profile of rAAV6 requires comprehensive evaluation for long-term safety.

Purpose of the Study:

• To comprehensively evaluate the chromosomal integration profile of rAAV6 in human CD34+ cells.
• To assess the genomic safety of rAAV6 for hematological gene therapy applications.

Main Methods:

• Human CD34+ cells were transduced with rAAV6 at varying doses and transgene contexts.
• Integration-site mapping was performed using integration-site enriched library sequencing.
• Functional enrichment and distance-based analyses were conducted on integration sites.

Main Results:

• High vector sequence alignment confirmed the largely episomal nature of rAAV6.
• rAAV6 integrations showed random, pan-chromosomal distribution without sequence-specific targeting.
• Integrations occurred in accessible chromatin regions (CpG islands) but not near oncogenes or tumor suppressor genes.

Conclusions:

• The integration profile of rAAV6 supports its genomic safety for gene therapy.
• rAAV6 demonstrates broad applicability for hematopoietic stem and progenitor cell-targeted gene therapy.
• Data suggest rAAV6 is a safe and effective vector for hematological gene therapy.