Combination of Coordination and Releasable Covalent Binding for the Delivery of Antisense Therapeutics by Bisphosphonate-Hyaluronan-Oligonucleotide Conjugates

Dmitri A Ossipov,Mads Lüchow,Samir El Andaloussi,Michael Malkoch,Oskar Gustafsson

doi:10.1021/acsapm.1c00243

Dmitri A Ossipov, Mads Lüchow + Show 3 more

Open Access

https://doi.org/10.1021/acsapm.1c00243

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Abstract

To address the current problems of delivery of antisense oligonucleotide (ON) therapeutics, a macromolecular platform was proposed based on the combination of metal-ion coordination and releasable covalent conjugation. Two kinds of therapeutic molecules, bisphosphonate (BP) and antisense ON, were conjugated to a natural polysaccharide hyaluronic acid (HA). The use of two linkers with a set of terminal chemoselective groups including N-hydroxysuccinimide carbonate, 2-dithiopyridyl, and aromatic aldehyde allowed orthogonal conjugation of the two therapeutics with subsequent detachment under potentially different conditions. In this work, disulfide linkages of varied steric accessibility were utilized in the linkers allowing the release of the linked therapeutics with different kinetics upon incubation in a reducing buffer. The therapeutics were conjugated to HA via their amino groups, and the self-immolative feature of the linkers permitted traceless release of both drugs as free amines. The obtained dual macromolecular prodrug was converted into either nanogels or macroscopic hydrogels upon coordination with calcium ions via Ca2+-mediated bridging of BP groups. Macroscopic hydrogels demonstrated self-healing properties which are useful for the noninvasive administration of ONs as biodegradable implants. Moreover, transformation of the macromolecular prodrug into a nanogel under dilute conditions is a useful property to prolong the circulation of the prodrug and protect antisense ON therapeutics against degradation in vivo.

Highlights

Antisense oligonucleotides (ONs) are promising therapeutics with a straightforward design based on hydrogen bonding with target nucleic acids that encode protein disease markers
We demonstrate that depending on the concentration of the hyaluronic acid (HA) carrier either nanogels or macroscopic hydrogels can be formed which can be utilized for systemic and localized delivery of ONs, respectively
Coordination binding of phosphodiester residues of nucleic acids to calcium ions lies in the basement of the small interfering RNA (siRNA) transfection method reported recently by Ruvinov et al.[21]

Summary

Introduction

Antisense oligonucleotides (ONs) are promising therapeutics with a straightforward design based on hydrogen bonding with target nucleic acids that encode protein disease markers. Different chemical modifications of nitrogen bases, sugar, and phosphate residues of ONs were performed[1] to impart chemical stability against nucleases and cell penetration properties to ONs which make such expensive therapeutics even more costly. Another way for the success of nucleic acid-based therapies relies on making releasable complexes with polymeric, inorganic, or hybrid nanomaterials.[2] limited success in this direction was achieved mainly due to toxicity and immunogenicity of the current biomaterials. Single-component ON biomaterials have been introduced to facilitate potent and specific interactions in a complex biological milieu.[3−6] none of the developed single-component ON biomaterials demonstrated the ability to disassemble and release the intact ON inside living cells despite the importance of the “off−on” dynamic features for drug delivery systems in vivo

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