Multivalent Lactobionic Acid and N-Acetylgalactosamine-conjugated Peptide Nucleic Acids for Efficient in vivo Targeting of Hepatocytes.

Peptide nucleic acids (PNAs) are used/applied in various studies to target genomic DNA and RNA to modulate gene expression. Non-specific targeting and rapid elimination always remain a challenge for PNA-based applications. Here, we report the synthesis, characterization, in vitro and in vivo study of di lactobionic acid and tris N-acetyl galactosamine conjugated PNAs for liver-targeted delivery. For proof of concept, we synthesized di lactobionic acid, and tris N-acetyl galactosamine conjugated anti-miR-122 PNAs targeting microRNA-122 (miR-122) that is over-expressed in the hepatic tissue. Different lengths of anti-miR-122 PNAs conjugated with di lactobionic acid and tris N-acetyl galactosamine were tested. We performed cell culture and in vivo analyses to determine biodistribution, efficacy, and toxicity profile. Our work indicated that di lactobionic acid conjugates showed significant retention in hepatocytes in addition to tris N-acetyl galactosamine conjugates after in vivo delivery. Full-length PNA conjugates showed significant downregulation of miR-122 levels and subsequent de-repression of its downstream targets with no evidence of toxicity. Our results provide a robust framework for ligand-conjugated delivery systems for PNAs that can be explored for broader biomedical applications. This article is protected by copyright. All rights reserved.