Targeted Delivery of Antisense Oligonucleotides Using Neurotensin Peptide

Despite recent advances, targeted delivery of therapeutic oligonucleotide to extra-hepatic tissues continues to be a challenging endeavor and efficient ligand-receptor systems need to be identified. To determine feasibility of using neurotensin to improve productive uptake of antisense oligonucleotides (ASO), we synthesized neurotensin-ASO conjugates and evaluated their cellular uptake and activity in cells and in mice. We performed a comprehensive structure-activity relationship (SAR) study of the conjugates and determined the influence of ASO charge, ASO length, peptide charge, linker chemistry and ligand identity on receptor-binding and internalization. We identified a modified neurotensin peptide capable of improving cellular uptake and activity of gapmer ASOs in sortilin expressing cells (6-fold) and in spinal cord in mice (2-fold). Neurotensin conjugation also improved potency of morpholino ASO designed to correct splicing of survival motor neuron (SMN2) pre-mRNA in cortex and striatum after intracerebroventricular injection. Neurotensin-mediated targeted delivery represents a possible approach for enhancing potency of ASOs with diverse nucleic acid modifications.