Bioconjugated Oligonucleotides: Recent Developments and Therapeutic Applications

Abstract

Oligonucleotide-based agents have the potential to treat or cure almost any disease, and are one of the key therapeutic drug classes of the future. Bioconjugated oligonucleotides, a subset of this class, are emerging from basic research and being successfully translated to the clinic. In this review, we first briefly describe two approaches for inhibiting specific genes using oligonucleotides -antisense DNA (ASO) and RNA interference (RNAi)followed by a discussion on delivery to cells. We then summarize and analyze recent developments in bioconjugated oligonucleotides including those possessing GalNAc, cell penetrating peptides, αtocopherol, aptamers, antibodies, cholesterol, squalene, fatty acids, or nucleolipids. These novel conjugates provide a means to enhance tissue targeting, cell internalization, endosomal escape, target binding specificity, resistance to nucleases, and more. We next describe those bioconjugated oligonucleotides approved for patient use or in clinical trials. Finally, we summarize the state of the field, describe current limitations, and discuss future prospects. Bioconjugation chemistry is at the centerpiece of this therapeutic oligonucleotide revolution, and significant opportunities exist for development of new modification chemistries, for mechanistic studies at the chemical-biology interface, and for translating such agents to the clinic.

Lipid oligonucleotides as a new strategy for tackling the antibiotic resistance

“…In this context, ONs represent a promising strategy to restore the resistant bacteria sensitivity to current antibiotics treatments, and in particular 3GCs 20,22 . However, despite their high potential, the cellular uptake of oligonucleotides remains one of the key steps for eliciting their biological activity, as the targeted mRNAs are located inside the cells 21,23 . Recently, we demonstrated that Lipid-oligonucleotide conjugates improve cellular uptake and efficiency of antisense in eukaryotic prostate cancer cells 24 .…”

Noncoding RNA in Liver Regeneration—From Molecular Mechanisms to Clinical Implications

“…Now, there are several efficient strategies for TNA delivery to the liver: lipid nanoparticles of various compositions and GalNAc conjugates that demonstrated exclusive delivery to hepatocytes via ASGP receptors, even in the case of subcuta-neous injections. 156,157 Heavily modified GalNAc-TNA conjugates can efficiently downregulate targets in the liver for up to 7 to 8 months after a single subcutaneous injection. 158 The main issue for TNA applications is off-target effects generated by downregulation of targets with partial complementarity to TNA.…”

Analytical and preparative separation of phosphorothioated oligonucleotides: columns and ion-pair reagents

“…This leads to peak broadening and increased difficulty in separating structurally very similar impurities. In a previous study [20] of PSmodified ONs, we found that selecting the ion-pair reagent in the eluent was crucial for the diastereomer selectivity and the use of trimethylammonium acetate followed by triethylammonium acetate resulted in the best selectivity. On the other hand, the use of tributyl ammonium acetate in the eluent suppressed diastereomer selectivity [20].…”

“…Much research has been focused on developing chromatographic methods to analyze phosphorothioate (PS)-modified ONs, which was recently summarized in a comprehensive review, including discussion about column chemistry and ion-pairing reagents [7]. A common separation challenge is the partial separation of the diastereomers introduced by the PS modification [7,[18][19][20]. This leads to peak broadening and increased difficulty in separating structurally very similar impurities.…”

“…In this study, we started out from the conclusions from the analytical study [20] and now focus on longer oligonucleotides, more similar in size as ASOs, i.e., around 15-25 nucleotides. In order to focus on the study on the effect of peak broadening due to partial diastereomer separation (see above), we will only consider homomeric oligonucleotides whose deletion products (n − 1, etc.)…”