Immunocompromised Cas9 transgenic mice for rapid in vivo assessment of host factors involved in highly pathogenic virus infection

• DOI: 10.1016/j.omtm.2021.09.012
• Publication Date: 2021-10-01T08:02:01Z
• Authors: Nicole Collette; Pragyesh Dhungel; Sean J. Lund; Jennifer L. Schwe...; Edwin A. Saada; Yooli K. Light; Anupama Sinha; Joseph S. Schoeniger; Oscar A. Negrete
• Keywords: 0301 basic medicine; in vivo delivery; QH573-671; lipid nanoparticles; QH426-470; NPC1; 3. Good health; Ebola virus; 03 medical and health sciences; CRISPR; Genetics; genome editing; Original Article; Cytology

Targeting host factors for anti-viral development offers several potential advantages over traditional countermeasures that include broad-spectrum activity and prevention of resistance. Characterization of host factors in animal models provides strong evidence of their involvement in disease pathogenesis, but the feasibility of performing high-throughput in vivo analyses on lists of genes is problematic. To begin addressing the challenges of screening candidate host factors in vivo, we combined advances in CRISPR-Cas9 genome editing with an immunocompromised mouse model used to study highly pathogenic viruses. Transgenic mice harboring a constitutively expressed Cas9 allele (Cas9 tg/tg ) with or without knockout of type I interferon receptors served to optimize in vivo delivery of CRISPR single-guide RNA (sgRNA) using Invivofectamine 3.0, a simple and easy-to-use lipid nanoparticle reagent. Invivofectamine 3.0-mediated liver-specific editing to remove activity of the critical Ebola virus host factor Niemann-Pick disease type C1 in an average of 74% of liver cells protected immunocompromised Cas9 tg/tg mice from lethal surrogate Ebola virus infection. We envision that immunocompromised Cas9 tg/tg mice combined with straightforward sgRNA in vivo delivery will enable efficient host factor loss-of-function screening in the liver and other organs to rapidly study their effects on viral pathogenesis and help initiate development of broad-spectrum, host-directed therapies against emerging pathogens.