Experimental Variables that Affect Human Hepatocyte AAV Transduction in Liver Chimeric Mice

Area of Science:

• Hepatology
• Gene Therapy
• Translational Medicine

Background:

• Adeno-associated virus (AAV) vectors are crucial for liver-directed gene therapies.
• Chimeric mouse models with human hepatocytes show promise for studying human liver diseases and therapies.
• Key factors influencing AAV transduction efficiency in these models require further definition.

Purpose of the Study:

• To investigate the impact of murine liver injury cycle, human donor variability, and AAV vector dose on AAV transgene expression.
• To assess how these variables affect hepatocyte transduction by different AAV serotypes in immunodeficient chimeric mice.

Main Methods:

• Utilized fumaryl-acetoacetate-hydrolase-deficient (Fah-/-) chimeric mice engrafted with primary human hepatocytes.
• Administered various AAV serotypes expressing green fluorescent protein (GFP) at different time points within the liver injury cycle.
• Analyzed GFP expression levels in human hepatocytes to quantify transduction efficiency and donor variability.

Main Results:

• Timing of AAV vector administration during the murine liver injury cycle altered GFP+ human hepatocyte percentages up to 7-fold.
• Human donor variability resulted in up to 7-fold differences in GFP+ hepatocyte frequency, without altering relative AAV serotype efficiency per donor.
• A direct correlation was observed between AAV vector dose and the extent of human hepatocyte transduction and transgene expression.

Conclusions:

• Experimental variables, including liver injury timing, donor origin, and vector dose, significantly influence AAV transduction in Fah-/- chimeric mouse models.
• Optimizing these parameters is essential for enhancing the reproducibility of findings across different research laboratories.
• These insights can refine the use of chimeric mouse models for preclinical evaluation of liver-directed gene therapies.