Expressions of CXCL9, CXCL10 and CXCL11 in renal tubular epithelial cells induced by IFN-γ

Objective: To investigate the effect of interferon-γ (IFN-γ) on the releases of CXCL9, CXCL10 and CXCL11 in renal proximal tubular epithelial cells (HK-2) and explore their functions.

Methods: After stimulated by IFN-γ for different time, the HK-2 cells were analyzed by real-time PCR to detect the expressions of CXCL9, CXCL10 and CXCL11 mRNA, and were tested by ELISA to quantify the releases of CXCL9, CXCL10 and CXCL11 in supernatants. After activation of lymphocytes, cells were examined by flow cytometry to determine the CXCR3 expression, while chemotaxis assay was applied to evaluate the chemotactic effect of the supernatants of IFN-stimulated HK-2 cells on lymphocytes.

Results: Compared with the control group, the expressions of CXCL9, CXCL10 and CXCL11 mRNA in the IFN-stimulated group were significantly increased 12 h after stimulation, and peaked at 48, 24 and 24 h, respectively. The levels of CXCL9, CXCL10 and CXCL11 proteins began to rise at 12 h and reached the peak at 72, 48 and 72 h, respectively. Compared with the control group, the expression of CXCR3 was markedly increased in the activated lymphocytes. The activated lymphocytes were recruited by the culture supernatants of IFN-stimulated HK-2 cells and the pretreatment of CXCR3 antibody inhibited this chemotactic effect.

Conclusions: IFN-γ can significantly up-regulate the expressions of chemokines such as CXCL9, CXCL10 and CXCL11 at both mRNA and protein levels in HK-2 cells.