Effects of miR-9 and tetramethylpyrazine on activation of hepatic stellate cells.

Micro-RNAs (miRNAs) are involved in regulation of the incidence and development of several hepatic diseases. Thus manipulating miRNAs may be a promising therapeutic strategy against these entities. In this study hepatic stellate cells (HSCs) were transfected with hsa-miR-9 or anti-hsa-miR-9, treated with tetramethylpyrazine (TMP), or subjected to treatment with TMP and hsa-miR-9 transfection (combined treatment group). Then, real-time polymerase chain reaction (PCR) was performed to measure mRNA levels of hsa-miR-9. Expression of hsa-miR-9 was highest in the combination treatment group compared with other groups, and significantly higher than TMP-treated and hsa-miR-9-transfected groups (both p<0.05). The anti-hsa-miR-9-transfected group expressed the lowest mRNA level of hsa-miR-9 with marked decrease versus control (p<0.05). Downstream factors that may be affected by miR-9 such as leptin, α-smooth muscle actin (SMA), and collagen I, as well as phosphorylation levels of Janus kinase 1 (JAK1)/signal transducer and activator of transcription 3 (STAT3) were investigated at the protein level. All these factors were regulated contrariwise to expression trends of hsa-miR-9, showing the lowest level in the combination treatment group and highest level in anti-hsa-miR-9-transfected group. These results suggest that both transfection of hsa-miR-9 and TMP can lead to upregulated endogenous expression of hsa-miR-9, inhibit activation of JAK1/STAT3 signal pathway induced by leptin, and lead to reduction of α-SMA and collagen I-thus impeding activation of HSC.