Figure 7.

NF-κB signaling is critical for mediating RANTES induction in tubular epithelial cells. (A) Inhibition of NF-κB signaling abrogated RANTES induction by TNF-α in tubular epithelial cells. HKC-8 cells were treated with 2 ng/ml TNF-α in the absence or presence of NF-κB inhibitor (NF-κB SN50). Cell lysates were immunoblotted with antibodies against RANTES and actin, respectively. (B) Ectopic expression of p65 NF-κB sensitized tubular epithelial cells to express RANTES in response to a low level of TNF-α stimulation. HKC-8 cells were transfected with either p65 NF-κB expression vector or pcDNA3 empty vector as indicated, followed by incubation with a low level of TNF-α (0.2 ng/ml) in the presence or absence of paricalcitol (10⁻⁷ M). Western blot showed that ectopic expression of p65 NF-κB rendered HKC-8 cells more sensitive to the stimulation with low concentration of TNF-α to express RANTES, whereas this effect was largely blocked by paricalcitol.