FIGURE 6.

N-Ras modulates LPS-induced cholangiocyte proliferation through IL6. A, cholangiocytes were transfected with N-Ras siRNA (50 nm) for 24 h. Proliferation was assessed using the CellTiter 96 Aqueous One Solution Cell Proliferation Assay. Cells treated with LPS (200 ng/ml) exhibited a significant (*, p < 0.05) increase in proliferation 24 h after LPS treatment compared with uninfected cells. However N-Ras depletion using the N-Ras siRNA significantly reduced LPS-induced cholangiocyte proliferation (#, p < 0.05) compared with the LPS-treated cells in the absence of N-Ras siRNA. B, to functionally validate the importance of IL6 autocrine signaling in LPS-induced proliferation the cells were treated with LPS or IL6 in the absence or presence of the IL6R-blocking antibody or a control, nonspecific isotype-matched control antibody. The proliferation assay was performed 24 h after treatment. In the absence of the IL6R-blocking antibody, LPS and IL6 significantly increased cholangiocyte proliferation (*, p < 0.05) compared with control cholangiocytes. In contrast, when the cells were pretreated with IL6-blocking antibody the proliferation rates following LPS or IL6 treatment were significantly reduced (*, p < 0.05) compared with treated cells cultured in the presence of the control Ab.