Role of the AAV receptor in AAV cell entry and trafficking

Abstract

Adeno-associated virus (AAV) has emerged as a promising delivery platform for gene therapies due to its relative safety and potential for long-term efficacy. However, the use of AAV is limited by its reliance on the cellular AAV receptor (AAVR) which is ubiquitously expressed, leading to broad tropism of AAV. Additionally, AAVR-binding residues on the AAV capsid are commonly recognized by the immune system, leading to neutralization of AAV vectors. Although AAVR is required for cell entry, its interactions with AAV are not well understood. Increased knowledge of the role of AAVR will allow for rational design of AAV capsids to improve safety and expand use while retaining function. This project asked whether the role of AAVR in transduction is passive, a means for AAV to enter the correct trafficking pathway; or active, where binding-induced structural changes are necessary. To this end, modified versions of AAV2 and AAVR which do not interact on their own were artificially targeted to each other through complementary peptide tag and nanobody insertions. Preliminary results demonstrate that artificial targeting does not rescue AAV transduction, suggesting that the role of AAVR may not be purely passive. However, further studies are needed to identify the step at which transduction is unsuccessful for the artificially targeted variants and how AAVR contributes to AAV transduction.