GalNAc-CPP conjugates enhance hepatocyte-nuclear delivery of oligonucleotide drugs in vivo

Antisense oligonucleotides (ASOs) offer a promising approach for gene expression modulation through mechanisms like exon skipping or transcript degradation. However, their clinical utility is hampered by poor cellular uptake, uncontrolled intracellular trafficking, and various barriers that prevent them from reaching their nuclear targets. Both splice-switching ASOs and mRNA-degrading ASOs, which rely on RNase H, require effective nuclear delivery to achieve maximum therapeutic efficacy. Addressing this critical gap in targeted delivery, especially to the nucleus of specific cell types like hepatocytes, is essential for unlocking the full therapeutic potential of ASOs.

Researchers developed a novel hepatocyte-targeted oligonucleotide delivery system by conjugating cell-penetrating peptides (CPP) with triantennary N-acetyl galactosamine (GalNAc, GN3). This GalNAc-CPP conjugate system was specifically engineered to overcome the inherent limitations of ASO delivery, focusing on enhancing cellular uptake and precise intracellular trafficking. The team evaluated the efficacy of these conjugates in vivo, assessing their ability to improve the delivery of both fluorescent dyes and antisense oligonucleotides (ASOs) to target cells. The primary objective was to demonstrate enhanced delivery efficiency and nuclear targeting for these oligonucleotide drugs.

The GalNAc-CPP conjugates successfully enhanced the delivery efficiency of both fluorescent dyes and antisense oligonucleotides (ASOs) in vivo. This improvement was specifically observed in the context of hepatocyte-nuclear targeting, a crucial step for ASO mechanisms of action. The novel delivery system effectively addressed the challenges of low cellular uptake and intracellular barriers that typically compromise ASO efficacy. By facilitating better access to the nucleus, the conjugates support the primary functions of ASOs, such as splice-switching and mRNA degradation via RNase H activity. This targeted approach ensures that ASOs reach their intended site of action, maximizing their therapeutic potential.

The developed GalNAc-CPP system provides an effective strategy for hepatocyte-nuclear-targeted drug delivery, overcoming limitations of conventional ASO administration and improving their overall therapeutic index.