Abstract

CRISPR/Cas9 Gene Editing of MIR155HG in Primary Human T Cells to Prevent Acute Graft-versus-Host Disease

Ramiro Garzon, Assoc Professor, The Ohio State University

Acute graft-versus-host disease (aGVHD) is the primary cause of non-relapse mortality in patients receiving an allogeneic hematopoietic cell transplant. Previously we showed miR-155 is necessary for development of aGVHD. Thus, there is an unmet need to target miR-155 using different strategies. To overcome this problem, we propose to delete miR-155 host gene (HG) in primary T cells from human donors using CRISPR/Cas9 genome editing. We identified three pairs of guideRNAs targeting the promoter or exon 3 (Ex3) of MIR155HG, all of which exhibited expected deletion sizes confirmed by genomic PCR and significantly reduced expression of mature miR-155 transcript relative to non-targeting control guide. Digital droplet PCR and whole genome sequencing followed by CHURCHILL genome analysis was used to identify on and off target effects. To assess in vivo function, we performed xenogeneic aGVHD transplants using MIR155HG edited or control T cells injected into NSG mice. Recipients of MIR155HG deleted T cells displayed significantly lower aGVHD clinical scores (p<0.01) and significantly improved survival compared to mice receiving control T cells. In summary, our studies support the development of genome editing of MIR155HG in primary human T cells as a strategy to prevent aGVHD.