The miR-22–5p/Clec4e axis has diagnostic potential in fructose-induced nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is significantly influenced by microRNAs in its development and progression. This study aimed to identify microRNA profiles and RNA regulatory networks for NAFLD intervention. Mice were fed a high-fructose diet (HFrD) to induce NAFLD. Small RNA-seq and mRNA-seq were used to analyze liver microRNA and mRNA profiles of HFrD-fed versus normal chow-fed (Chow) mice. The differentially expressed genes (DEGs) and miRNAs (DE-miRNAs) were identified, followed by enrichment analysis. A protein‒protein interaction network of overlapping DEGs and DE-miRNA targets was constructed, along with a competing endogenous RNA (ceRNA) network. Mendelian randomization (MR) was performed to verify the causal relationship between top DEGs and NAFLD. The study identified 13 DE-miRNAs and 854 DEGs in the liver between HFrD mice and Chow mice. A Venn diagram revealed that 58 of the predicted target genes of the 13 DE-miRNAs were shared with the DEGs. Finally, 6 DE-miRNAs, 34 DEGs, and 20 predicted lncRNAs were selected to construct the ceRNA regulatory network. The upregulated DEG Clec4e, a target gene of miR-22-5p, was significantly correlated with the risk of NAFLD (OR: 1.41, 95 % CI: 1.04-1.92, P = 0.029) in the MR analysis, and RT-qPCR was applied to validate Clec4e expression in the livers of HFrD mice. Further, the dual-luciferase reporter assay confirmed that miR-22-5p could directly inhibit Clec4e expression by targeting its 3'-UTR. This study identified several novel miRNAs and genes as potential biomarkers of NAFLD. In particular, the miR-22-5p/Clec4e axis is a potential diagnostic target for NAFLD.