HepG2.2.15-derived exosomes facilitate the activation and fibrosis of hepatic stellate cells

To elucidate the effect of exosomes derived from HepG2.2.15 cells on the activation of hepatic stellate cell (HSC) LX2 and the progression of liver fibrosis.

The role of exosomes derived from HepG2.2.15 cells, which express hepatitis B virus (HBV)-related proteins, in triggering the activation of LX2 liver stellate cells and promoting liver fibrosis and cell proliferation remains elusive. The focus was on comprehending the relationship and influence of differentially expressed microRNAs (DE-miRNAs) within these exosomes.

These findings suggest that exosomes from HepG2.2.15 cells play a substantial role in the activation, proliferation, and fibrosis of LX2 cells and that DE-miRNAs within these exosomes contribute to the underlying mechanisms.

Exosomes from HepG2.2.15 cells, which express HBV-related proteins, were isolated from parental HepG2 and WRL68 cells. Western blotting was used to confirm the presence of the exosomal marker protein CD9. The activation of HSCs was assessed using oil red staining, whereas DiI staining facilitated the observation of exosomal uptake by LX2 cells. Additionally, we evaluated LX2 cell proliferation and fibrosis marker expression using 5-ethynyl-2'-deoxyuracil staining and western blotting, respectively. DE-miRNAs were analyzed using DESeq2. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were used to annotate the target genes of DE-miRNAs.

Exosomes from HepG2.2.15 cells were found to induced activation and enhanced proliferation and fibrosis in LX2 cells. A total of 27 miRNAs were differentially expressed in exosomes from HepG2.2.15 cells. GO analysis indicated that these DE-miRNA target genes were associated with cell differentiation, intracellular signal transduction, negative regulation of apoptosis, extracellular exosomes, and RNA binding. KEGG pathway analysis highlighted ubiquitin-mediated proteolysis, the MAPK signaling pathway, viral carcinogenesis, and the toll-like receptor signaling pathway, among others, as enriched in these targets.