[Effects of exogenous transforming growth factor-β3 on the activities of its promoter and cAMP-responsive element binding protein-1 in rat hepatic stellate cell].

OBJECTIVE

To explore the effects of exogenous transforming growth factor-β3 (TGF-β3) on the activities of its promoter and cAMP-responsive element binding protein-1 (CREB-1) in rat hepatic stellate cell (HSC-T6).

METHODS

HSC-T6 was cultured and treated with or without exogenous TGF-β3 (10 µg/L). Then cell extracts, total RNA and nuclear proteins were collected at different time points. The specimens were detected by luciferase reporter assay, Western blotting and real-time RT-PCR (reverse transcription-polymerase chain reaction) respectively.

RESULTS

After treatment, the activity of TGF-β3 promoter peaked at 24 h (10.68 ± 0.57 vs 4.83 ± 0.56, 2.2 folds vs control). And the mutational CRE site completely blocked the activity of TGF-β3 promoter (0.73 ± 0.03, P < 0.05). In addition, exogenous TGF-β3 increased the expression of phospho-CREB-1 in a time-dependent manner. It peaked at 1 h (2.0 folds vs control) and declined slowly. And exogenous TGF-β3 had no effect on the mRNA and protein expressions of CREB-1 (P > 0.05).

CONCLUSION

The activity of TGF-β3 promoter is up-regulated by exogenous TGF-β3. And CRE site in TGF-β3 promoter region is important for the transcription of TGF-β3 gene in HSC-T6. While activating CREB-1, exogenous TGF-β3 has no effect on the expressions of CREB-1 protein and mRNA.