Development of a novel platform to enhance intracellular bioavailability of antisense morpholino oligomers

DESCRIPTION provided by applicant Peptide conjugated phosphorodiamidate morpholino oligomers PPMO are single stranded nucleic acid analogs able to modulate gene expression through steric blocking of complementary RNA PPMO are composed of two components an antisense morpholino oligomer cargo covalently conjugated to a cell penetrating delivery peptide PPMO are completely nuclease resistant water soluble and enter cells without assistance These characteristics represent distinct advantages over other antisense technologies PPMO have shown considerable potential against a wide range of clinical targets including several genetic disorders and numerous viral pathogens However the challenge of intracellular endosomal trapping of PPMO is hampering continued clinical development of this class of antisense therapeutics requiring increased doses of PPMO to achieve clinical efficacy and narrowing the therapeutic window for this promising technology The primary objective of this project is to improve the PPMO therapeutic window through the novel combination of an established cell penetrating peptide with endosome disruptive viral fusion peptide motifs We hypothesize that this will enhance intracellular release thus improving the access of the antisense cargo to its RNA targets within the cytosol of cells As a model system to validate this innovative delivery approach we will assess in vitro efficacy using our previously established dengue virus model Dengue virus is a complex human pathogen currently causing a major global public health problem yet despite the acute need no licensed antiviral to treat dengue virus infections is currently available Through this application we have assembled a multidisciplinary team of researchers with unique expertise in nucleic acid delivery technologies Dr Moulton Oregon State University as well as an industry partner Dr Amanna Naj t Technologies Inc each team with andgt years of experience in early stage antiviral clinical development By significantly improving the delivery and activity of the PPMO platform this project is expected not only to enhance the utility of PPMO as a therapeutic class but also to provide a novel strategy for addressing dengue virus infections in humans At the conclusion of this project we anticipate a novel and improved PPMO platform that can be applied to a wide range of clinical targets

PUBLIC HEALTH RELEVANCE Peptide conjugated morpholino oligomers PPMO are completely nuclease resistant DNA analogs that enter cells readily and represent an important delivery system for antisense agents However this therapeutic potential is hampered by limited bioavailability primarily due to endosomal trapping We propose to develop novel combinations of viral fusion and cell penetrating peptides to enhance endosomal release of the antisense component of PPMO using dengue virus as a clinically relevant proof of concept target This project will not only develop a PPMO inhibitor against an important human pathogen but will also represent a major advance in the development of this significant therapeutic platform