Development of a Novel Method to Detect AAV Vector Integration

Area of Science:

• Molecular Biology
• Genetics
• Gene Therapy

Background:

• Adeno-associated virus (AAV) integration is critical for gene therapy safety.
• Existing methods for detecting AAV integration sites are limited by biases from library preparation, sequencing, and bioinformatics.

Purpose of the Study:

• To develop a novel, unbiased method for characterizing AAV DNA integration sites.
• To overcome the limitations of PCR-based amplification in detecting AAV integration.

Main Methods:

• Developed a PCR-free amplification strategy using CRISPR-Cas9 cleavage for AAV DNA.
• Combined this strategy with long-read nanopore sequencing for unbiased integration junction detection.
• Validated the method using AAV-transduced HeLa single-cell clones and compared it with probe hybridization capture and short-read sequencing.

Main Results:

• The CRISPR-Cas9-based, PCR-free workflow accurately identified AAV integration junctions.
• Strong consistency was observed between the novel method and probe hybridization capture/short-read sequencing.
• The approach preserves native AAV integration states.

Conclusions:

• The developed CRISPR-Cas9-enabled, PCR-free long-read sequencing workflow is a promising tool for characterizing AAV integration events.
• This method offers an unbiased approach to AAV integration site analysis, crucial for gene therapy safety.