Improving Antisense Oligonucleotide Binding to Human Serum Albumin: Dramatic Effect of Ibuprofen Conjugation

Development of DNA Nanostructures for High-Affinity Binding to Human Serum Albumin

“…When all available binding sites on HSA are occupied by D1, Unlike other methods to modify albumin covalently, our specific and non-covalent binding between D-DNA and HSA is complete within minutes at room temperature. Moreover, previous hydrophobic modifications (e.g., ibuprofen, 15 cholesterol, tocopherol, 30 or phosphorothioate backbone 31 introduced in DNA) have yielded low affinity (micromolar) binding to HSA, whereas our current SPR data are consistent with previous literature describing high affinity (nanomolar) binding of fatty acids to HSA (10 7 −10 8 M −1 association constants). 32 The dendritic alkyl structure may help to overcome the electrostatic repulsion between the DNA and the protein by providing a multivalent ligand to interact with the multiple sites on HSA.…”

“…For example, Manoharan and co-workers conjugated ibuprofen to an antisense oligonucleotide, which in turn bound to HSA with micromolar affinity. 15 White and co-workers also conjugated siRNAs to a free cysteine residue on HSA, allowing for extravasation of the siRNA and silencing effect in cardiomyocytes. 16 To improve upon the half-life of DNA-based therapeutics and DNA nanostructures, their biodistribution, and cellular uptake, we wanted to develop a new strategy to complex DNA with HSA.…”

“…To date, very few reports in the literature have examined the potential of HSA to circumvent such issues for oligonucleotide delivery. For example, Manoharan and co-workers conjugated ibuprofen to an antisense oligonucleotide, which in turn bound to HSA with micromolar affinity . White and co-workers also conjugated siRNAs to a free cysteine residue on HSA, allowing for extravasation of the siRNA and silencing effect in cardiomyocytes …”

Effect of Phosphothioate Modification on the Anti-L-Tyrosinamide Aptamer

“…Phosphothioate modifications, as mentioned, take place in an aptamer's backbone where the nonbridging oxygen atom in the phosphate backbone is substituted with a sulfur atom. There have been extensive studies done on antisense oligonucleotides that depict the effects this modification has on binding and stability 15 . Later, a few studies investigated and discovered the positive effects of phosphothioate modification on aptamer stability, binding, resistance to nuclease degradation, and fixation to proteins thereby prolonging the aptamer's half-life and reducing renal clearance 16,17 .…”