Fig 3.

The upregulation of OSTα mRNA by hypoxia and CDCA is dependent on HIF-1α and FXR. The figure shows the relative OST mRNA levels in Huh7 after transfection with siRNA targeting HIF-1α or FXR. The results of each treatment condition (CDCA, hypoxia, or both) are shown relative to cells transfected with a random scrambled siRNA (siControl). The figure shows average results of at least three independent experiments, with *P < 0.05, **P < 0.01 and ***P < 0.001. (a) Knock-down of HIF-1α significantly reduces the induction of OSTα mRNA in cells treated with CDCA or hypoxia, either alone or in combination. As expected, a knock-down of FXR abrogates the inducing effect of CDCA on OSTα mRNA expression. (b) While knock-down of FXR significantly reduces the inducing effect of CDCA on OSTβ mRNA expression, HIF-1α knock-down does not influence the induction of OSTβ mRNA in cells treated with CDCA under either normoxic or hypoxic conditions.