Antiviral immunity and nucleic acid sensing in haematopoietic stem cell gene engineering

Abstract

The low gene manipulation efficiency of human hematopoietic stem and progenitor cells (HSPC) remains a major hurdle for sustainable and broad clinical application of innovative therapies for a wide range of disorders. Given that all current and emerging gene transfer and editing technologies are bound to expose HSPC to exogenous nucleic acids and most often also to viral vectors, we reason that host antiviral factors and nucleic acid sensors play a pivotal role in the efficacy of HSPC genetic manipulation. Here, we review recent progress in our understanding of vector–host interactions and innate immunity in HSPC upon gene engineering and discuss how dissecting this crosstalk can guide the development of more stealth and efficient gene therapy approaches in the future.

Optimization of AAV6 transduction enhances site-specific genome editing of primary human lymphocytes

“…AAV vectors are invaluable reagents for site-specific genome editing of human hematopoietic cells, with AAV6 serotypes in particular being widely used to deliver homology donors to HSPCs, 2 , 4 , 11 , 12 T cells, 13 , 14 , 15 and B cells. 16 , 17 , 19 The in vitro tropism of AAV6 for human hematopoietic cells, 2 , 13 , 16 as well as its weak induction of innate immune pathways that could trigger harmful biological consequences in engineered cells, 42 , 43 may contribute to its success. In addition, the vector’s ability to transduce both dividing and quiescent cells 44 may also be beneficial, particularly if the genome is used as a homology template only after second-strand synthesis as some have suggested, 7 though the G2/S phase restriction of cellular factors required for HDR 25 may limit the advantages conferred by this attribute.…”

Sensing Stemness

“…Although RLRs and cGAS-STING are non-essential genes, animals and humans with mutations in RLRs, cGAS-STING, or downstream signaling components are prone to immune dysregulation, such as autoimmunity and infectious susceptibility [100]. Additionally, antiviral immunity plays a central role in stem cell gene engineering [101]. The recent work from our groups and others indicate that these sensing pathways could also titrate stemness properties.…”

Optimization of AAV6 transduction enhances site-specific genome editing of primary human lymphocytes

“…AAV vectors are invaluable reagents for site-specific genome editing of human hematopoietic cells, with AAV6 serotypes in particular being widely used to deliver homology donors to HSPCs, 2,4,11,12 T cells, [13][14][15] and B cells. 16,17,19 The in vitro tropism of AAV6 for human hematopoietic cells, 2,13,16 as well its weak induction of innate immune pathways that could trigger harmful biological consequences in engineered cells, 41,42 may contribute to its success. In addition, the vector's ability to transduce both dividing and quiescent cells 43 may also be beneficial, particularly if the genome is used as a homology template only after second-strand synthesis as some have suggested, 7 though the G2/S phase restriction of cellular factors required for HDR 25 may limit the advantages conferred by this attribute.…”