Non-nuclear localization signal-guided CRISPR/Cas9 ribonucleoproteins for translocation and gene editing via apoferritin delivery vectors

Abstract

Direct delivery of the Cas9/sgRNA ribonucleoprotein (RNP) via appropriate carriers has been proved to be an important advance for the in vivo translocation and gene editing of CRISPR/Cas9. These carriers often require the nuclear localization signal (NLS) to fuse with Cas9 or the NLS-bearing protein to form a complex with Cas9 to enter the nucleus. In this study, we introduced apoferritin nanocages as carriers and DOX as a nuclear trigger for the nuclear transport of the Cas9/sgRNA ribonucleoprotein without the NLS (RNP⁻). Our experiments showed that loading RNP⁻ and DOX into 4L-FTH subunit-based apoferritin nanocages leads to efficient endocytosis and lysosomal escape. Specifically, when DOX was administered at a concentration of 1 μM, we observed the activation of cellular defense mechanisms, which effectively facilitated the translocation of 4L-HFn@RNP⁻/DOX nanoparticles into the nucleus, thereby enabling intranuclear RNP⁻ delivery. This strategy has been empirically demonstrated to achieve gene editing efficiencies of approximately 33% for the Lcn2 gene in MDA-MB-231 cells and 17.9% for the copepod green fluorescent protein (copGFP) gene in HeLa.copGFP cells in vitro. Moreover, in vivo editing efficacy, as tested in a HeLa.copGFP nude mouse model, was confirmed to be 16%. This delivery system presents a novel therapeutic approach for the nuclear delivery of small molecules or nucleic acid drugs, potentially overcoming the challenges associated with nuclear entry barriers.