Determination of five nucleosides by LC‐MS/MS and the application of the method to quantify N6‐methyladenosine level in liver messenger ribonucleic acid of an acetaminophen‐induced hepatotoxicity mouse model

Ribonucleic acid N6 -methyladenosine methylation plays an important role in a variety of biological processes and diseases. Acetaminophen-induced hepatotoxicity is one of the major challenges faced by clinicians. To date, the link between N6 -methyladenosine and acetaminophen-induced hepatotoxicity has not been studied. In this study, a simple ultra high performance liquid chromatography with tandem mass spectrometry method was developed for the simultaneous determination of five nucleosides (adenosine, uridine, cytidine, guanosine, and N6 -methyladenosine) in messenger ribonucleic acid. After enzymatic digestion of messenger ribonucleic acid, the nucleosides sample was separated on an Acquity UPLC column with gradient elution using methanol and 0.02% formic acid water, and detected by a Qtrap 4500 mass spectrometer with an electrospray ionization mode. The method was validated over the concentration ranges of 4-800 ng/mL for adenosine, uridine, cytidine, and guanosine and 0.1-20 ng/mL for N6 -methyladenosine. It was successfully applied to the determination of N6 -methyladenosine levels in liver messenger ribonucleic acid in an acetaminophen-induced hepatotoxicity mouse model and a control group. This study offers a method for the determination of nucleoside contents in epigenetic studies and constitutes the first step toward the investigation of ribonucleic acid methylation in acetaminophen-induced hepatotoxicity, which will facilitate the elucidation of its mechanism.