A Rationally Designed AAV9-DM Capsid with Minimal Liver Tropism

Area of Science:

• Gene Therapy
• Viral Vector Engineering
• Molecular Biology

Background:

• Adeno-associated viral vectors (AAV) are prominent in gene therapy.
• AAV9 offers broad tissue tropism and central nervous system penetration.
• Systemic AAV9 administration faces challenges with high liver transduction rates and toxicity, hindering extrahepatic tissue targeting.

Purpose of the Study:

• To develop an AAV9 variant with reduced liver tropism for safer systemic gene therapy.
• To engineer a novel AAV9 capsid that minimizes off-target liver transduction while preserving extrahepatic targeting.

Main Methods:

• Rational design principles were applied to the AAV9 capsid.
• Five point mutations were introduced into the AAV9 capsid to create the AAV9-DM variant.
• In vivo studies were conducted to assess transduction efficiency, transgene expression, and biodistribution.

Main Results:

• A novel AAV9 variant, AAV9-DM, was successfully developed.
• AAV9-DM demonstrated significantly reduced liver tropism compared to wild-type AAV9.
• The AAV9-DM variant showed effective in vivo transduction and robust transgene expression over 9 weeks.
• AAV9-DM maintained biodistribution similar to AAV9, enabling transduction of non-hepatic tissues.

Conclusions:

• The AAV9-DM capsid represents a promising advancement for gene therapy.
• This engineered AAV variant offers a potential strategy to enhance the safety of systemic gene therapies by reducing liver toxicity.
• AAV9-DM may facilitate targeted gene delivery to extrahepatic tissues, minimizing adverse effects associated with liver transduction.