Targeted, safe, and efficient gene delivery to human hematopoietic stem and progenitor cells invivousing the engineered AVID adenovirus vector platform

Targeted delivery and cell-type-specific expression of gene-editing proteins in various cell types in vivorepresent major challenges for all viral and non-viral delivery platforms developed to date. Here, we describe the development and analysis of artificial vectors for intravascular delivery (AVIDs), an engineered adenovirus-based gene delivery platform that allows for highly targeted, safe, and efficient gene delivery to human hematopoietic stem and progenitor cells (HSPCs) in vivoafter intravenous vector administration. Due to a set of refined structural modifications, intravenous administration of AVIDs did not trigger cytokine storm, hepatotoxicity, or thrombocytopenia. Single intravenous administration of AVIDs to humanized mice, grafted with human CD34+cells, led to up to 20% transduction of CD34+CD38−CD45RA−HSPC subsets in the bone marrow. Importantly, targeted in vivotransduction of CD34+CD38−CD45RA−CD90−CD49f+subsets, highly enriched for human hematopoietic stem cells (HSCs), reached up to 19%, which represented a 1,900-fold selectivity in gene delivery to HSC-enriched over lineage-committed CD34-negative cell populations. Because the AVID platform allows for regulated, cell-type-specific expression of gene-editing technologies as well as expression of immunomodulatory proteins to ensure persistence of corrected HSCs in vivo, the HSC-targeted AVID platform may enable development of curative therapies through in vivogene correction in human HSCs after a single intravenous administration.