iPSC-hepatocyte organoids as a novel platform to predict AAV gene therapy efficacy

Adeno-associated virus (AAV) vectors are widely used in gene therapy, particularly for liver-targeted treatments. However, predicting human-specific outcomes, such as transduction efficiency and hepatotoxicity, remains challenging. Reliable <i>in vitro</i> models are urgently needed to bridge the gap between preclinical studies and clinical applications. This study presents the first comparative evaluation of AAV transduction across multiple induced pluripotent stem cell (iPSC)-derived hepatocyte organoid donors, offering a novel platform for assessing vector performance in human liver models. The transduction efficiency and hepatotoxicity of eight AAV serotypes (AAV1, AAV2, AAV3, AAV4, AAV5, AAV6, AAV8, and AAV9) were tested in iPSC-derived liver organoids and hepatic cell lines (HepG2 and HepaRG). AAV6 and AAV8 exhibited the highest transduction efficiency in organoids, while AAV4 and AAV5 were the least effective. Transduction variability was observed across different donors and cell lines. Notably, no significant hepatotoxicity, measured by AST (aspartate aminotransferase) release and viability measurements, was observed, indicating that AAVs do not induce immediate liver damage <i>in vitro</i>. This study introduces iPSC-derived hepatocyte organoids as a novel and effective tool for predicting AAV transduction efficiency and safety, with potential to enhance the translation of gene therapies to clinical applications.