Interleukin-1 beta up-regulates tissue inhibitor of matrix metalloproteinase-1 mRNA and phosphorylation of c-jun N-terminal kinase and p38 in hepatic stellate cells.

AIM

To study the relationship between interleukin-1beta (IL-1beta) up-regulating tissue inhibitor of matrix metalloproteinase-1 (TIMMP-1) mRNA expression and phosphorylation of both c-jun N-terminal kinase (JNK) and p38 in rat hepatic stellate cells (HSC).

METHODS

RT-PCR was performed to measure the expression of TIMMP-1 mRNA in rat HSC. Western blot was performed to measure IL-1beta-induced JNK and p38 activities in rat HSC.

RESULTS

TIMMP-1 mRNA expression (1.191+/-0.079) was much higher after treatment with IL-1beta (10 ng/mL) for 24 h than in control group (0.545+/-0.091) (P<0.01). IL-1beta activated JNK and p38 in a time-dependent manner. After stimulation with IL-1beta for 0, 5, 15, 30, 60 and 120 min,the JNK activity was 0.982+/-0.299,1.501+/-0.720, 2.133+/-0.882, 3.360+/-0.452, 2.181+/-0.789, and 1.385+/-0.368, respectively. There was a significant difference in JNK activity at 15 min (P<0.01), 30 min (P<0.01) and 60 min (P<0.01) in comparison to that at 0 min. The p38 activity was 1.061+/-0.310,2.050+/-0.863, 2.380+/-0.573, 2.973+/-0.953, 2.421+/-0.793, and 1.755+/-0.433 at the 6 time points (0, 5, 15, 30, 60 and 120 min) respectively. There was a significant difference in p38 activity at 5 min (P<0.05),15 min (P<0.01), 30 min (P<0.01) and 60 min (P<0.01) compared to that at 0 min.TIMMP-1 mRNA expression trended to decrease in 3 groups pretreated with different concentrations of SP600125 (10 micromol/L, 1.022+/-0.113; 20 micromol/L, 0.869+/-0.070; 40 micromol/L, 0.666+/-0.123). Their decreases were all significant (P<0.05, P<0.01, P<0.01) in comparison to control group (without SP600125 treatment, 1.163+/-0.107). In the other 3 groups pretreated with different concentrations of SB203580 (10 micromol/L, 1.507+/-0.099; 20 micromol/L, 1.698+/-0.107; 40 micromol/L,1.857+/-0.054), the expression of TIMMP-1 mRNA increased. Their levels were higher than those in the control group (without SB203580 treatment, 1.027+/-0.061) with a significant statistical significance (P<0.01).

CONCLUSION

IL-1beta has a direct action on hepatic fibrosis by up-regulating TIMMP-1 mRNA expression in rat HSC. JNK and p38 mitogen-activated protein kinases (MAPKs) are involved in IL-1beta-induced TIMMP-1 gene expression,and play a distinct role in this process, indicating that p38 and JNK pathways cooperatively mediate TIMP-1 mRNA expression in rat HSC.