The foundational adenine base editors (e.g. ABE7.10) enable programmable C•G to T•A point mutations but editing efficiencies can be low at challenging loci in primary human cells. Here we further evolve ABE7.10 using a library of adenosine deaminase variants to create ABE8s. At NGG PAM sites, ABE8s result in ~1.5x higher editing at protospacer positions A5-A7 and ~3.2x higher editing at positions A3-A4 and A8-A10 compared with ABE7.10. Non-NGG PAM variants have a ~4.2-fold overall higher on-target editing efficiency than ABE7.10. In human CD34+ cells, ABE8 can recreate a natural allele at the promoter of the γ-globin genes HBG1 and HBG2, with up to 60% efficiency, causing persistence of fetal hemoglobin. In primary human T cells, ABE8s achieve 98-99% target modification which is maintained when multiplexed across three loci. Delivered as mRNA, ABE8s induce no significant levels of sgRNA-independent off-target adenine deamination in genomic DNA and very low levels of adenine deamination in cellular mRNA.

Innovative and coordinated strategies to address weight bias among health professionals are urgently needed. We conducted a systematic literature review of empirical peer-reviewed published studies to assess the impact of interventions designed to reduce weight bias in students or professionals in a health-related field. Combination sets of keywords based on three themes (1: weight bias/stigma; 2: obesity/overweight; 3: health professional) were searched within nine databases. Our search yielded 1447 individual records, of which 17 intervention studies satisfied the inclusion criteria. Most studies (n = 15) included medical, dietetic, health promotion, psychology and kinesiology students, while the minority included practicing health professionals (n = 2). Studies utilized various bias-reduction strategies. Many studies had methodological weaknesses, including short assessment periods, lack of randomization, lack of control group and small sample sizes. Although many studies reported changes in health professionals' beliefs and knowledge about obesity aetiology, evidence of effectiveness is poor, and long-term effects of intervention strategies on weight bias reduction remain unknown. The findings highlight the lack of experimental research to reduce weight bias among health professionals. Although changes in practice will likely require multiple strategies in various sectors, well-designed trials are needed to test the impact of interventions to decrease weight bias in healthcare settings.

The foundational adenine base editors (e.g. ABE7.10) enable programmable C•G to T•A point mutations but editing efficiencies can be low at challenging loci in primary human cells. Here we further evolve ABE7.10 using a library of adenosine deaminase variants to create ABE8s. At NGG PAM sites, ABE8s result in ∼1.5x higher editing at protospacer positions A5-A7 and ∼3.2x higher editing at positions A3-A4 and A8-A10 compared with ABE7.10. Non-NGG PAM variants have a ∼4.2-fold overall higher on-target editing efficiency than ABE7.10. In human CD34+ cells, ABE8 can recreate a natural allele at the promoter of the γ-globin genes HBG1 and HBG2, with up to 60% efficiency, causing persistence of fetal hemoglobin. In primary human T cells, ABE8s achieve 98-99% target modification which is maintained when multiplexed across three loci. Delivered as mRNA, ABE8s induce no significant levels of sgRNA-independent off-target adenine deamination in genomic DNA and very low levels of adenine deamination in cellular mRNA.

Comparative studies should take into account the relationship between kappa and the prevalence of the events being measured.

Allogeneic chimeric antigen receptor T cell (CART) therapies require multiple gene edits to be clinically tractable. Most allogeneic CART have been created using gene editing techniques that induce DNA double-stranded breaks (DSBs), resulting in unintended on-target editing outcomes with potentially unforeseen consequences. Cytosine base editors (CBEs) install C•G to T•A point mutations in T cells with between 90-99% efficiency to silence gene expression without creating DSBs, greatly reducing or eliminating undesired editing outcomes following multiplexed editing as compared to CRISPR-Cas9. Using CBE, we developed 7CAR8, a CD7-directed allogeneic CART created using four simultaneous base edits. We show that CBE, unlike CRISPR-Cas9, does not impact T-cell proliferation, lead to aberrant DNA damage response pathway activation or result in karyotypic abnormalities following multiplexed editing. We demonstrate 7CAR8 to be highly efficacious against T-cell acute lymphoblastic leukemia (T-ALL) using multiple in vitro and in vivo models. Thus, CBE is a promising technology for applications requiring multiplexed gene editing and can be used to manufacture quadruple-edited 7CAR8 cells with high potential for clinical translation for relapsed and refractory T-ALL.