MiR-146a Is Screened and Confirmed to Inhibit TLR4-Dependent Immune of Hepatic Stellate Cells and Reduce Radiation-Induced Liver Disease

Background: To screen and confirm microRNAs(miRs) relating to TLR4-dependent immune, which may promote radiation-induced liver diseases (RILDs) by changing cytokines in liver microenvironments.Methods: Eighteen HCC patients, underwent surgical resection post-RT, were enrolled in this study. MiRs (has- let-7e, miR-9, miR-21, miR-34a, miR-122, miR-125, miR-146a, miR-155, and miR-200) were detected by qRT-PCR. MiR-146a was screened to inhibit TLR4-dependent immune and RILDs. Furthermore, Hepatic cells (HL-7702), cocultured with/without hepatic stellate cells (HSCs) (LX-2), were irradiated with 6 Gy. And, LX2 cells were overexpressed miR-146a-5p or not to evaluate that whether overexpressing miR-146a in LX-2 cells could reduce RILDs. Flow cytometry and AO/EB methods were used to detect mortality of HL-7702 cells 48h-post-RT. Expression levels of α-SMA/TLR4/miR-146a in LX2 cells and cytokines in cell supernatants were also detected.Results: Among the miRNAs, miR-146a and miR-200 were significantly related to TLR4 expression level in liver tissues (P=0.043 and 0.014). But, only miR-146a up-regulation was significantly correlated mild RILDs (P=0.025). In vitro, irradiation could significantly inhibit the expression level of miR-146a, but up-regulate that of TLR4 and α-SMA in LX-2 (P=0.016 and 0.0003), and up-regulate IL-1β, IL6, IL-8 and IL-12 expression in cell supernatants (P=0.002, 0.012, 0.018 and 0.049, respectively). The mortality proportion of HL-7702 cells co-cultured with LX-2 significantly increased than HL-7702 cells cultured alone 48h post-RT(P=0.003), but significantly decreased post-RT when HL-7702 cells co-cultured with LX-2 overexpressed miR-146a-5p and significantly down-regulated TLR4 expression.Conclusions: miR-146a was screened and confirmed to inhibit TLR4 dependent immune of HSCs and release RILDs.