Lipotoxic hepatocyte-derived exosomal miR-1297 promotes hepatic stellate cell activation through the PTEN signaling pathway in metabolic-associated fatty liver disease

BACKGROUND Exosomes play an important role in metabolic-associated fatty liver disease(MAFLD),but the mechanism by which exosomes participate in MAFLD still remain unclear.AIM To figure out the function of lipotoxic exosomal miR-1297 in MAFLD.METHODS MicroRNA sequencing was used to detect differentially expressed miRNAs(DEmiR)in lipotoxic exosomes derived from primary hepatocytes.Bioinformatic tools were applied to analyze the target genes and pathways regulated by the DE-miRs.Quantitative real-time PCR(qPCR)was conducted for the verification of DEmiRs.qPCR,western blot,immunofluorescence staining and ethynyl-20-deoxyuridine assay were used to evaluate the function of lipotoxic exosomal miR-1297 on hepatic stellate cells(LX2 cells).A luciferase reporter experiment was performed to confirm the relationship of miR-1297 and its target gene PTEN.RESULTS MicroRNA sequencing revealed that there were 61 exosomal DE-miRs(P<0.05)with a fold-change>2 from palmitic acid treated primary hepatocytes compared with the vehicle control group.miR-1297 was the most highly upregulated according to the microRNA sequencing.Bioinformatic tools showed a variety of target genes and pathways regulated by these DE-miRs were related to liver fibrosis.miR-1297 was overexpressed in exosomes derived from lipotoxic hepatocytes by qPCR.Fibrosis promoting genes(α-SMA,PCNA)were altered in LX2 cells after miR-1297 overexpression or miR-1297-rich lipotoxic exosome incubation via qPCR and western blot analysis.Immunofluorescence staining and ethynyl-20-deoxyuridine staining demonstrated that the activation and proliferation of LX2 cells were also promoted after the above treatment.PTEN was found to be the target gene of miR-1297 and knocking down PTEN contributed to the activation and proliferation of LX2 cells via modulating the PI3K/AKT signaling pathway.CONCLUSION miR-1297 was overexpressed in exosomes derived from lipotoxic hepatocytes.The lipotoxic hepatocyte-derived exosomal miR-1297 could promote the activation and proliferation of hepatic stellate cells through the PTEN/PI3K/AKT signaling pathway,accelerating the progression of MAFLD.