miR-15b and miR-16 are implicated in activation of the rat hepatic stellate cell: An essential role for apoptosis

Background/Aims To reveal the microRNA (miRNA) expression profile and related roles in rat HSCs during activation. Methods miRNA expression profiling was analyzed in quiescent and in culture-activated HSCs by microarray. The differentially expressed miRNAs, as verified by RT-PCR, were subjected to gene ontology (GO) analysis. Furthermore, the effects of miR-16 and miR-15b on the apoptosis of activated HSCs were investigated by Hoechst 33258, TUNEL staining and annexin-V/PI labeling flow cytometry. The underlying mechanism related to Bcl-2 and caspases was assessed. Results The upregulated and downregulated miRNAs in activated HSCs were 12 miRNAs and 9 miRNAs, respectively. The differential expression of miR-16, -15b, -122, -138, -143, and -140 was validated. High-enrichment GOs containing apoptosis-related targeted genes and miRNA–gene networks characterized by Bcl-2, which was targeted by the miR-15/16 family, uncovered the critical role of miR-16 and miR-15b in apoptosis. Restoring the intracellular miRNAs by miR-16 and miR-15b administration greatly reduced Bcl-2, and increased the expression of caspases 3, 8, and 9. Significantly elevated rates of apoptosis were then induced in activated HSCs. Conclusions The activation of HSCs relate to 21 miRNAs. Among these, mir-15b and miR-16 may be essential for apoptosis by targeting Bcl-2 and the caspase signaling pathway.