Membrane-derived particles cloaked in membrane fragments can deliver CRISPR genome editing tools to specific cells for complex genome engineering inside the body. Scientists in the lab of Nobel Prize winner Jennifer Doudna, PhD, created enveloped delivery vehicles (EDVs) that can carry Cas9 and gRNA proteins for precise genome editing in living organisms. This work establishes a programmable delivery modality with the potential for widespread therapeutic utility.

The research article, “In vivo human T cell engineering with enveloped delivery vehicles,” was published in Nature Biotechnology.

Targeted in vivo delivery of genome editing tools

Safe and efficient delivery of molecules into target cell nuclei is essential for genome editing therapeutic interventions. However, current nonviral delivery methods are limited to treating cells outside the body or directly targeting tissues or the liver because of its innate ability to absorb molecules. When delivering molecular cargo, it’s becoming more common to use cellular fragments to cloak particles like extracellular vesicles, biomimetic nanoparticles, and retrovirus-like particles.

The Doudna lab researchers at the Innovative Genomics Institute (IGI) engineered EDVs that use the lentivirus’s ability to package molecules and transduce cells and antibodies’ ability to recognize cells on the surface. After that, these EDVs were used to send Cas9 protein, sgRNAs, and transgenes to specific cells in a culture of human cells.

In addition, Jennifer R. Hamilton, PhD, and colleagues used mice with humanized immune systems to show in vivo targeting of human cells (albeit not in humans). In particular, they showed that antibody-directed EDVs edit the genomes of humanized mice without transducing hepatocytes. As a proof of concept to show targeted genome editing in vivo, the Doudna lab researchers generated human chimeric antigen receptor (CAR) T cells in mice with a humanized immune system.

While no treatment-related toxicity was observed following T-cell-targeted EDV administration in vivo, it will be important for future studies to assess the impact of EDV dose on triggering aberrant T-cell activation and proliferation. While the report concentrates on the engineering of human immune cells, the researchers mentioned that non-immune cells will also be the subject of future research, emphasizing the targeted in vivo engineering of tissue-resident stem cells.

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