Genome-wide identification of altered RNA m⁶A profiles in vascular tissue of septic rats

Sepsis is the leading cause of death in hospital intensive care units. In light of recent studies showing that variations in N⁶-methyladenosine (m⁶A) levels in different RNA transcripts influence inflammatory responses, we evaluated the m⁶A profiles of rat aortic mRNAs and lncRNAs after lipopolysaccharide (LPS)-induced sepsis. LC-MS-based mRNA modification analysis showed that global m6A levels were significantly decreased in aortic tissue of rats injected intraperitoneally with LPS. This finding was consistent with downregulated expression of METTL3 and WTAP, two members of the m⁶A writer complex, in LPS-exposed aortas. Microarray analysis of m⁶A methylation indicated that 40 transcripts (31 mRNAs and 9 lncRNAs) were hypermethylated, while 223 transcripts (156 mRNAs and 67 lncRNAs) were hypomethylated, in aortic tissue from LPS-treated rats. On GO and KEGG analyses, 'complement and coagulation cascades', 'transient receptor potential channels', and 'organic anion transmembrane transporter activity' were the major biological processes modulated by the differentially m⁶A methylated mRNAs. In turn, competing endogenous RNA network analysis suggested that decreased m⁶A levels in lncRNA-XR_343955 may affect the inflammatory response through the cell adhesion molecule pathway. Our data suggest that therapeutic modulation of the cellular m⁶A machinery may be useful to preserve vascular integrity and function during sepsis.