Distribution of Antisense Oligonucleotides in Rat Eyeballs Using MALDI Imaging Mass Spectrometry

Abstract

Oligonucleotide-based therapeutics such as antisense oligonucleotides, small interfering RNAs (siRNAs), decoy and aptamer have been extensively developed. To investigate the pharmacokinetics of oligonucleotide therapeutics, it is common to label a radioisotope in a nucleic acid and visualize it. However, if the labeled terminal nucleotide is decomposed by a nuclease in vivo, only the labeled nucleotide is detected, and it is impossible to observe the nucleic acid exhibiting the drug effect. The distribution of biomolecules, such as phospholipids, proteins, and glycolipids, can be obtained and visualized without labeling using matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS). MALDI-IMS is also used in pharmacokinetic analysis to visualize a parent drug and its metabolites simultaneously. In this study, we reported a methodology for oligonucleotides analysis by MALDI-IMS. When phosphorothioate antisense oligonucleotide was administered into the eyeball of rats, it reached the retina after 30 min without undergoing decomposition by nucleases.

Development of sheet‐enhanced technique (Set) method for matrix‐assisted laser desorption/ionization imaging mass spectrometry

“…The advantage of the MALDI method is that it uses soft ionization that does not destroy the compound of interest. Therefore, MALDI‐IMS has been developed to reveal the distribution of biomolecules, such as phospholipids, proteins, glycolipids, and oligonucleotides . MALDI‐IMS is also used for pharmacokinetic analyses, to visualize a parent drug and its metabolites simultaneously …”

“…Therefore, MALDI-IMS has been developed to reveal the distribution of biomolecules, such as phospholipids, 1-6 proteins, 7-9 glycolipids, 10,11 and oligonucleotides. 12,13 MALDI-IMS is also used for pharmacokinetic analyses, to visualize a parent drug and its metabolites simultaneously. [14][15][16] The key to successful experiments in MALDI-IMS is to apply the matrix uniformly to the sample since the ratio of matrix to molecule greatly affects ionization.…”

Use of mTRAQ derivatization reagents on tissues for imaging neurotransmitters by MALDI imaging mass spectrometry: the triple spray method

“…One disadvantage of this method is the reliance on the analyte to be ionizable. However, with increase in the number of studies, the ranges of matrices [4] and derivatization reagents [5] are expanding, allowing for a wider range of analytes to be detected [6, 7]. It is important to be able to quantitatively compare the data for their use in drug development.…”

The role of fluoroalcohols as counter anions for ion‐pairing reversed‐phase liquid chromatography/high‐resolution electrospray ionization mass spectrometry analysis of oligonucleotides

“…Both electrospray ionization (ESI) and matrix‐assisted laser desorption/ionization (MALDI) have been substantially applied in the characterization of oligonucleotides. However, a major problem accompanied with mass measurement of oligonucleotides is multiple adduct ions associated with oligonucleotides species, as a result of strong affinity of the polyanionic backbone in oligonucleotide molecules to various cations including sodium and potassium .…”