Molecular Signature of Astrocytes for Gene Delivery by the Synthetic Adeno-Associated Viral Vector rAAV9P1

Abstract

Astrocytes have crucial functions in the central nervous system (CNS) and are major players in many CNS diseases. Research on astrocyte-centered diseases requires efficient and well-characterized gene transfer vectors. Vectors derived from the Adeno-associated virus serotype 9 (AAV9) target astrocytes in the brains of rodents and nonhuman primates. A recombinant (r) synthetic peptide-displaying AAV9 variant, rAAV9P1, that efficiently and selectively transduces cultured human astrocytes, has been described previously. Here, it is shown that rAAV9P1 retains astrocyte-targeting properties upon intravenous injection in mice. Detailed analysis of putative receptors on human astrocytes shows that rAAV9P1 utilizes integrin subunits αv, β8, and either β3 or β5 as well as the AAV receptor AAVR. This receptor pattern is distinct from that of vectors derived from wildtype AAV2 or AAV9. Furthermore, a CRISPR/Cas9 genome-wide knockout screening revealed the involvement of several astrocyte-associated intracellular signaling pathways in the transduction of human astrocytes by rAAV9P1. This study delineates the unique receptor and intracellular pathway signatures utilized by rAAV9P1 for targeting human astrocytes. These results enhance the understanding of the transduction biology of synthetic rAAV vectors for astrocytes and can promote the development of advanced astrocyte-selective gene delivery vehicles for research and clinical applications.Recombinant Adeno-associated virus vector 9P1 (rAAV9P1) is a peptide-displaying variant of AAV9 that targets human (in vitro) and murine (in vivo) astrocytes with high efficiency. rAAV9P1 utilizes the integrins αvβ8 and αvβ3 or αvβ5, glycan residues and the AAV receptor (AAVR) to transduce astrocytes. Various astrocyte-relevant intracellular pathways also contribute to efficient transduction of astroyctes by rAAV9P1.