Safe and effective in vivo delivery of DNA and RNA using proteolipid vehicles

Genetic medicines show promise for treating various diseases, yet clinical success has been limited by tolerability, scalability, and immunogenicity issues of current delivery platforms. To overcome these, we developed a proteolipid vehicle (PLV) by combining features from viral and non-viral approaches. PLVs incorporate fusion-associated small transmembrane (FAST) proteins isolated from fusogenic orthoreoviruses into a well-tolerated lipid formulation, using scalable microfluidic mixing. Screening a FAST protein library, we identified a chimeric FAST protein with enhanced membrane fusion activity that improved gene expression from an optimized lipid formulation. Systemically administered FAST-PLVs showed broad biodistribution and effective mRNA and DNA delivery in mouse and non-human primate models. FAST-PLVs show low immunogenicity and maintain activity upon repeat dosing. Systemic administration of follistatin DNA gene therapy with FAST-PLVs raised circulating follistatin levels and significantly increased muscle mass and grip strength. These results demonstrate the promising potential of FAST-PLVs for redosable gene therapies and genetic medicines. [Display omitted] •Adding FAST protein to a lipid formulation increases mRNA and pDNA expression•FAST-PLVs show high degrees of extrahepatic gene delivery with mRNA and pDNA•The low immunogenicity of the FAST-PLV platform enables repeat dosing•Systemically administered FAST-PLVs facilitate therapeutic pDNA gene expression Current genetic medicines are limited by tolerability, scalability, and immunogenicity issues. Utilizing components from viral and non-viral delivery platforms, we developed a lipid-based delivery vehicle formulated with a chimeric fusion protein that delivers nucleic acid cargo inside cells effectively and with broad distribution and low immunogenicity. This proteolipid vehicle platform is suitable for safe and effective repeat dosing of DNA and/or RNA in vivo.