Abstract: Compositions and methods for delivering nucleoprotein cargos such as Cas9-RNP genome editing and ABE-Cas9-RNP base editing complexes to the cytosolic/nuclear compartment of eukaryotic cells via synthetic peptide shuttle agents are described herein. Also described herein are shortened synthetic peptide shuttle agents having a length of less than 20 amino acids having defined geometries associated with cargo transduction activity. The synthetic peptide shuttle agents are peptides comprising an amphipathic alpha-helical motif having both a positively-charged hydrophilic outer face and a hydrophobic outer face, wherein the synthetic peptide shuttle agent is independent from or is not covalently linked to the cargoes. Shuttle agents engineered for increased resistance to inhibition by nucleoproteins and/or extracellular DNA/RNA are also described herein.

Abstract: Compositions and methods for delivering non-anionic polynucleotide analog cargoes to the cytosolic/nuclear compartment of eukaryotic cells via a synthetic peptide shuttle agent are described herein. The non-anionic polynucleotide analog cargoes may be charge-neutral or cationic, and the synthetic peptide shuttle agent is a peptide comprising an amphipathic alpha-helical motif having both a positively-charged hydrophilic outer face and a hydrophobic outer face, wherein synthetic peptide shuttle agent is not covalently linked, or linked in a cleavable manner under physiological conditions, to the non-anionic polynucleotide analog cargoes. The non-anionic polynucleotide analog cargo may be a charge-neutral or cationic antisense synthetic oligonucleotide (ASO) that hybridizes to an intracellular target RNA for gene expression modification.

Abstract: Described herein are methods, compositions, kits and synthetic peptide shuttle agents relating to the transduction of proteinaceous and/or non-proteinaceous cargoes. The method generally comprises contacting target eukaryotic cells with a non-proteinaceous cargo and a concentration of a synthetic peptide shuttle agent sufficient to increase the transduction efficiency of the non-proteinaceous cargo, as compared to in the absence of said synthetic peptide shuttle agent. In embodiments, the non-proteinaceous cargo may be a drug, such as a small molecule drug, for treating a disease. In other embodiments, novel synthetic peptide shuttle agents having transduction activity for proteinaceous and/or non-proteinaceous cargoes are described, as well as the use of propidium iodide or other membrane-impermeable fluorescent DNA intercalating agent as a surrogate cargo for selecting versatile synthetic peptide shuttle agents having transduction activity for both proteinaceous and non-proteinaceous cargoes.

Abstract: Compounds of formula I: wherein X, R2, R3, R5 and R6 are defined herein, are useful as inhibitors of the hepatitis C virus NS5B polymerase.