302. Combinatorial Engineering of a Receptor Footprint on AAV Serotype 4 Yields Novel Vectors
Year: 2015
Type: article
Abstract: Most AAV strains in clinical development display a broad range of cellular tropisms within the central nervous system (CNS). As such, this current panel of vectors provides several options for efficient gene expression within neurons and/or glia in the brain. However, precise therapeutic interventions will require selective targeting of distinct cell populations within the brain and other organs, such as the eye. In this regard, a select few AAV serotypes have demonstrated unique tissue tropisms following systemic or peripheral routes of administration. One such example, originally isolated from African green monkeys, is AAV4. This serotype is one of the most divergent serotypes identified to date. From a structural perspective, AAV4 has several unique surface loop topologies that are consistent with the remarkably different usage of receptors, cellular tropism and unique antigenicity displayed by this serotype. Specifically, AAV4 is known to utilize O-linked sialoglycans, or mucins, for cell surface attachment. In the current study, through a combination of structural analysis and random mutagenesis, we identified several key amino acids for further genetic manipulation. Saturation mutagenesis of key residues within a broad receptor footprint on the AAV4 capsid surface yielded a highly diverse library, which was subjected to screening as well as directed evolution in a panel of cell lines in vitro. Additional screening and directed evolution studies in vivo in the mouse CNS yielded several novel AAV4 variants that display distinct transduction profiles in the brain. Extensive in silico analyses, structural modeling, and biological characterization of the novel panel of AAV strains is currently in progress.
Source: Molecular Therapy
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
OpenAlex ID: W2564198519