Optimizing CRISPR/Cas9 genome editing in primary human hematopoietic cells to advance studies into HIV biology

Defining how human host factors shape HIV-1 infection in vivo remains essential for the development of genetically engineered cell therapies. Here, we established a non-viral CRISPR/Cas9 ribonucleoprotein-based platform for efficient single and multiplex gene editing in primary human CD34+ hematopoietic stem and progenitor cells (HSPCs). Edited HSPCs retained viability, proliferative capacity, primitive immunophenotypes, and multilineage differentiation potential and supported targeted reporter knock-in independently of the cell source, cord blood (CB), bone marrow (BM), and mobilized from peripheral blood (MPB). Following differentiation, SAMHD1 knockout increased HIV-1 susceptibility of HSPC-derived macrophages, MX2 knockout also increased HIV infection in cells pre-stimulated with IFN-2a, and CXCR4 knockout blocked X4-tropic HIV-1 infection of HSPC-derived megakaryocytes. We then transplanted CCR5-, SAMHD1-, or non-targeting control-edited HSPCs into immunodeficient mice and challenged reconstituted animals with R5-tropic HIV-1. CCR5 knockout prevented detectable viral spread, validating the model using a clinically relevant dependency factor. In contrast, SAMHD1 knockout accelerated viral dissemination, with earlier plasma viremia and 3.6-fold higher cumulative viremia, although endpoint viral burden was not significantly different from controls. These findings establish transplantation of CRISPR/Cas9-edited human HSPCs as a modular platform for dissecting HIV-1 host-factor function across hematopoietic lineages ex vivo and in vivo and for evaluating engineered cell-based strategies.