Interaction of notch signaling pathway with toll-like receptor 4 on the function of CD14+ monocytes in chronic hepatitis C patients

Abstract

Objective: To observe the expressional changes in Notch signaling pathway and toll-like receptor 4 (TLR4) and their interactions on the functions of CD14(+) monocytes in chronic hepatitis C patients. Methods: A total of 24 treatment-naïve chronic hepatitis C cases and 10 healthy individuals, who visited Shaanxi Provincial People's Hospital from August to October 2017, were enrolled. Selected CD14(+) monocytes were stimulated by the Notch signaling pathway inhibitor DAPT or transfected with TLR4 siRNA, and the levels of Notch1, Notch2, Hes1 and Hes5 mRNA were detected by real-time quantitative PCR. TLR4 protein levels and phosphorylation of NF-κB was detected by Western blot. ELISA was used to detect the level of cytokines secreted from CD14(+) monocytes. A t-test or paired t-test was used for comparison between groups. Results: The relative expression of Notch1 mRNA (3.97 ± 2.03 vs. 0.91 ± 0.76, P < 0.01) and downstream of Notch signaling pathway (5.96 ± 2.31 vs. 0.99 ± 0.45, P < 0.01), Hes1 mRNA and Hes5 mRNA (4.31 ± 1.05 vs. 0.84 ± 0.20, P < 0.01) in CD14+ monocytes of chronic hepatitis C patients was significantly higher than that of healthy individuals. The relative expression of TLR4 mRNA (5.14 ± 1.09 vs. 1.27 ± 0.39) and protein level in CD14(+) monocytes of chronic hepatitis C patients were significantly higher than those of healthy individuals (P < 0.01). An inhibition of Notch signaling pathway with DAPT had reduced the relative expression level of TLR4 mRNA (2.58 ± 1.36 vs. 4.34 ± 1.88, P < 0.05), protein expression and phosphorylation of NF-B in CD14(+) monocytes of chronic hepatitis C patients. Furthermore, the secretion level of MCP-1 [(94.32 ± 23.59) pg/ml vs. (64.07 ± 9.39) pg/ml, P < 0.01] and IL-8 [(12.54 ± 4.89) pg/ml vs. (7.92 ± 3.01) pg/ml, P < 0.05] was significantly reduced. TLR4 siRNA transfection reduced the expressions of Notch1 mRNA (2.09 ± 1.72 vs. 3.73 ± 1.75, P < 0.05), Hes1 (2.87 ± 0.84 vs. 5.54 ± 0.97, P < 0.01), and Hes5 (2.89 ± 0.93 vs. 4.51 ± 1.54, P < 0.01) in CD14(+) monocytes of chronic hepatitis C patients. Conclusion: Interaction of Notch signaling pathway with TLR4 can promote the function of CD14(+) monocytes in chronic hepatitis C patients.