Abstract
Transplantation of allogenic hematopoietic stem and progenitor cells (HSPCs) with C-C chemokine receptor type 5 (CCR5) Δ32 genotype generates HIV-1 resistant immune cells. CCR5 gene edited autologous HSPCs can be a potential alternative to hematopoietic stem cell transplantation (HSCT) from HLA-matched CCR5 null donor. However, the clinical application of gene edited autologous HSPCs is critically limited by the quality of the graft, as HIV also infects the HSPCs. In this study, by using mobilized HSPCs from healthy donors, we show that the CD34+CD90+ hematopoietic stem cells (HSCs) express 7-fold lower CD4/CCR5 HIV receptors, higher levels of SAMHD1 anti-viral restriction factor, and possess lower susceptibility to HIV infection than the CD34+CD90- hematopoietic progenitor cells. Further, the treatment with small molecule cocktail of Resveratrol, UM729 and SR1(RUS) improved the in vivo engraftment potential of CD34+CD90+ HSCs. To demonstrate that CD34+CD90+ HSC population as an ideal graft for HIV gene therapy, we sort purified CD34+CD90+ HSCs, treated with RUS and then gene edited the CCR5 with single sgRNA. On transplantation, 100,000 CD34+CD90+ HSCs were sufficient for long-term repopulation of the entire bone marrow of NBSGW mice. Importantly, the gene editing efficiency of ~90% in the infused product was maintained in vivo, facilitating the generation of CCR5 null immune cells, resistant to HIV infection. Altogether, CCR5 gene editing of CD34+CD90+ HSCs provide an ideal gene manipulation strategy for autologous HSCT based gene therapy for HIV infection.
Highlights
Human immunodeficiency virus-1 (HIV-1) infection leads to acquired immunodeficiency syndrome (AIDS) and more than 30 million people are affected by it worldwide [1]
(33) was expressed 2.5-fold higher in CD34+CD90+ hematopoietic stem cells (HSCs) (Figure 2G). All these findings suggest that reduced expression of HIV receptors and presence of higher levels of antiviral restriction factors are mediating the resistance of CD34+CD90+ HSCs to HIV infection
These findings suggest that CD34+CD90+ HSCs are ideal target cells for chemokine receptor type 5 (CCR5) gene manipulation for HIV gene therapy
Summary
Human immunodeficiency virus-1 (HIV-1) infection leads to acquired immunodeficiency syndrome (AIDS) and more than 30 million people are affected by it worldwide [1]. Viral replication in patients is suppressed by lifetime antiretroviral therapy (ART). HIV infects the immune cells through the receptors such as CD4, CCR5 and CXCR4, which are predominantly expressed on the host immune cells such as T cells, macrophages and dendritic cells [4]. These receptors are the potential targets to block HIV invasion and destruction of critical immune cells [5, 6]. The CCR5 receptor is an attractive target owing to a naturally occurring CCR5 null variant (CCR5 delta32/delta32), which confers resistance to R5-tropic HIV-1 [7]. HSPCs from CCR5 null homozygous individuals have been shown to impart functional cure to AIDS patients on allogeneic transplantation [7, 8]. The limited availability of HLA matched CCR5 null donors, in African and south-Asian populations with high prevalence of HIV, poses major challenge to this approach as a regular therapy [10]
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