LncRNA A2ml2 inhibits fatty liver hemorrhage syndrome progression and function as ceRNA to target LPL by sponging miR-143-5p.

Fatty liver hemorrhage syndrome (FLHS) is the most common metabolic diseases in laying hens during the late-laying period, and it causes a significant economic burden on the poultry industry. The competing endogenous RNA plays crucial roles in the occurrence and development of fatty liver. Based on the previously constructed lncRNA-miRNA-mRNA networks, we selected the axis of ENSGALT00000079786-LPL-miR-143-5p for further study to elucidate its mechanistic role in development of fatty liver. In this study, we identified a novel highly conserved lncRNA (ENSGALT00000079786) in poultry, which we designated as lncRNA A2ml2 based on its chromosomal location. Fluorescent in situ hybridization (FISH) revealed that lncRNA A2ml2 was localized in both the nucleus and cytoplasm. Dual-luciferase reporter assay validated the targeted relationship between lncRNA A2ml2, miR-143-5p, and the LPL gene. To further analyze the lncRNA A2ml2 and miR-143-5p function, lncRNA A2ml2 overexpression vector was successfully constructed and transfected into Leghorn male hepatocellular (LMH) cells, which could remarkably inhibit cellular lipid deposition was detected by oil red staining (P < 0.01), the opposite occurred for miR-143-5p (P < 0.01). qPCR demonstrated an inverse correlation between miR-143-5p expression and lncRNA A2ml2 expression, and confirmed that miR-143-5p directly target lncRNA A2ml2. Similarly, we found an inverse correlation between expression of LPL and the expression of miR-143-5p. To further investigate the interactions among these three factors and their effects on cellular lipid metabolism, we assessed the expression levels of LPL by co-transfecting lncRNA A2ml2 with miR-143-5p mimic and miR-143-5p mimic binding site mutants. Co-transfection experiments showed that miR-143-5p diminished the promoting effect of lncRNA A2ml2 on LPL. Meanwhile, miR-143-5p has the capacity to mitigate the suppressive impact of lncRNA A2ml2 overexpression on lipid accumulation in LMH cells. The results revealed that lncRNA A2ml2 attenuated hepatic lipid accumulation through negatively regulating miR-143-5p and enhancing LPL expression in LMH cells. Our findings offer novel insights into ceRNA-mediated in FLHS and identify a novel lncRNA as a potential molecular biomarker.