[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-β3promoter 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 TGFβ3 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. Key words: Liver cirrhosis;  Transforming growth factor beta3;  Cyclic AMP response elementbinding protein