m6A Methylation Mediated Autophagy and Nucleotide-Binding Oligomerization Domain-like Receptors Signaling Pathway Provides New Insight into the Mitigation of Oxidative Damage by Mulberry Leaf Polysaccharides.

m6A methylation modification is an important genetic modification involved in biological processes such as sexual maturation, antibacterial, and antiviral in aquatic animals. However, few studies have been conducted in aquatic animals on the relationship between m6A methylation modification and autophagy-inflammation induced by lipid metabolism disorders. In the present study, a high-fat (HF) group and HF-MLP group (1 g mulberry leaf polysaccharides (MLPs)/1 kg HF diet) were set up. The mid-hind intestines of Megalobrama amblycephala juveniles from the two groups were collected for MeRIP-seq and RNA-seq after an 8-week feeding trial. The m6A peaks in the HF and HF-MLP groups were mainly enriched in the 3' Untranslated Region (3'UTR), Stop codon, and coding sequence (CDS) region. Compared with the HF group, the m6A peaks in the HF-MLP group were shifted toward the 5'UTR region. 'RRACH' was the common m6A methylation motif in the HF and HF-MLP groups. Methyltransferase mettl14 and wtap expression in the intestines of the HF-MLP group were significantly higher compared with the HF group (p < 0.05). A total of 21 differentially expressed genes(DEGs) with different peaks were screened by the combined MeRIP-seq and RNA-seq analysis. Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis enriched BCL2 interacting protein 3 (bnip3) to autophagy-animal and mitophagy-animal signaling pathways, etc., and nucleotide-binding domain leucine-rich repeat protein 1 (nlrp1) was enriched to the Nucleotide-binding oligomerization domain (NOD)-like receptor signaling pathway. Combined MeRIP-seq and RNA-seq analysis indicated that the expression pattern of bnip3 was hyper-up and that of nlrp1 was hyper-down. Gene Set Enrichment Analysis (GSEA) analysis confirmed that the intestinal genes of HF-MLP group positively regulate lysosomal and autophagy-animal signaling pathways. In the present study, we demonstrated that m6A methylation modification plays a role in regulating autophagy-inflammatory responses induced by HF diets by MLPs, and further explored the molecular mechanisms by which MLPs work from the epigenetic perspective.