Superior In vivo Transduction of Human Hepatocytes Using Engineered AAV3 Capsid

Area of Science:

• Gene Therapy
• Virology
• Hepatology

Background:

• Adeno-associated viral (AAV) vectors are crucial for liver-directed gene therapy in clinical trials for hemophilia and metabolic disorders.
• Identifying optimal AAV capsids for human hepatocyte transduction is critical but yields inconsistent results across models.

Purpose of the Study:

• To evaluate and compare the in vivo transduction efficiency of different AAV serotypes in human hepatocytes using humanized mouse models.
• To identify the most effective AAV capsid for gene transfer in human liver cells.

Main Methods:

• Utilized "humanized" mice with chimeric livers containing human and murine hepatocytes.
• Optimized flow cytometry and confocal microscopy with image analysis to quantify AAV transduction rates.
• Administered self-complementary AAV vectors expressing a GFP reporter gene via peripheral vein injection.

Main Results:

• An engineered AAV3 capsid (AAV3-ST) exhibited significantly higher efficiency for human hepatocyte transduction compared to AAV9, AAV8, and AAV5.
• AAV9, AAV8, and AAV5 showed greater transduction efficiency in murine hepatocytes than in human hepatocytes.
• AAV8 demonstrated the highest transduction rate in murine hepatocytes, significantly exceeding that in human hepatocytes.

Conclusions:

• Substantial differences exist in AAV serotype transduction efficiencies between human and mouse hepatocytes.
• This study provides the first report on AAV5 performance in humanized mice.
• AAV3-based vectors are promising candidates for efficient human liver gene transfer.