Résumé
miR-146a is an immunoregulatory microRNA closely associated with viral infection. This study investigated the expression changes of miR-146a in peripheral blood monocytes of HCV-infected patients and the mechanism by which the THP-1 cells were stimulated with HCV core protein in vitro. It was found that in the peripheral blood monocytes of HCV-infected patients, miR-146a expression was upregulated. After treated by interferon/ribavirin, miR-146a expression was decreased when HCV RNA became undetectable. HCV core could directly stimulate THP-1 cells to produce miR-146a. Silencing TLR2 and MyD88 could significantly inhibit the expression of miR-146a. It was concluded that the expression of miR-146a in peripheral blood monocytes of HCV-infected patients was abnormally increased. The TLR2-MyD88 signaling pathway may take part in the overexpression of miR-146a in monocytes stimulated with HCV core protein.
Résumé
miR-146a is an immunoregulatory microRNA closely associated with viral infection. This study investigated the expression changes of miR-146a in peripheral blood monocytes of HCV-infected patients and the mechanism by which the THP-1 cells were stimulated with HCV core protein in vitro. It was found that in the peripheral blood monocytes of HCV-infected patients, miR-146a expression was upregulated. After treated by interferon/ribavirin, miR-146a expression was decreased when HCV RNA became undetectable. HCV core could directly stimulate THP-1 cells to produce miR-146a. Silencing TLR2 and MyD88 could significantly inhibit the expression of miR-146a. It was concluded that the expression of miR-146a in peripheral blood monocytes of HCV-infected patients was abnormally increased. The TLR2-MyD88 signaling pathway may take part in the overexpression of miR-146a in monocytes stimulated with HCV core protein.
Sujets)
Adulte , Femelle , Humains , Mâle , Adulte d'âge moyen , Jeune adulte , Séquence nucléotidique , Lignée cellulaire , Amorces ADN , Hépatite C chronique , Sang , microARN , Sang , Monocytes , Métabolisme , Facteur de différenciation myéloïde-88 , Physiologie , RT-PCR , Récepteur de type Toll-2 , PhysiologieRésumé
The activation of hepatic stellate cells (HSCs) and their transformation to myofibroblasts are the key steps in the pathological progress of liver fibrosis. The transforming growth factor-β (TGFβ)/Smad pathway is involved in the proliferation and collagen synthesis of HSCs. This study aimed to examine the effect of the protease inhibitor MG132 on the signaling pathway of TGFβ/Smad in HSC-T6 cells and seek a novel therapeutic approach for liver fibrosis. The HSC-T6 cells were treated with MG132 at different concentrations (0-10 μmol/L). Cell proliferation was detected by MTT method. The mRNA and protein expression levels of TGFβ1, Smad3 and Smad7 were determined in HSC-T6 cells by real-time PCR and Western blotting, respectively, after treatment with MG132 at different concentrations (1, 2, 3 μmol/L) or RPMI1640 alone (serving as control). The results showed that MG132 could inhibit the proliferation of HSC-T6 cells in a dose-dependent manner, and the IC(50) of MG132 was 6.84 μmol/L. After treatment with MG132 at 1, 2 or 3 μmol/L for 24 h, the mRNA expression levels of TGF-β1 and Smad3 were significantly decreased (P<0.05), but the Smad7 mRNA expression had no significant change (P>0.05). There was also a significant decrease in the protein expression level of TGF-β1 and Smad3 (P<0.05). However, the expression of Smad7 protein was substantially increased when compared with the control group (P<0.05). It was concluded that the inhibition of TGFβ/Smad pathway in HSC-T6 cells by MG132 can reduce the production of profibrosis factors (TGFβ1, Smad3) and promote the expression of anti-fibrosis factor (Smad7), suggesting that MG132 may become a potential therapeutic alternative for liver fibrosis.
Sujets)
Animaux , Rats , Lignée cellulaire , Leupeptines , Pharmacologie , Inhibiteurs de protéases , Pharmacologie , Transduction du signal , Protéines Smad , Métabolisme , Facteur de croissance transformant bêta , MétabolismeRésumé
The activation of hepatic stellate cells (HSCs) and their transformation to myofibroblasts are the key steps in the pathological progress of liver fibrosis. The transforming growth factor-β (TGFβ)/Smad pathway is involved in the proliferation and collagen synthesis of HSCs. This study aimed to examine the effect of the protease inhibitor MG132 on the signaling pathway of TGFβ/Smad in HSC-T6 cells and seek a novel therapeutic approach for liver fibrosis. The HSC-T6 cells were treated with MG132 at different concentrations (0-10 μmol/L). Cell proliferation was detected by MTT method. The mRNA and protein expression levels of TGFβ1, Smad3 and Smad7 were determined in HSC-T6 cells by real-time PCR and Western blotting, respectively, after treatment with MG132 at different concentrations (1, 2, 3 μmol/L) or RPMI1640 alone (serving as control). The results showed that MG132 could inhibit the proliferation of HSC-T6 cells in a dose-dependent manner, and the IC50 of MG132 was 6.84 μmol/L. After treatment with MG132 at 1, 2 or 3 μmol/L for 24 h, the mRNA expression levels of TGF-β1 and Smad3 were significantly decreased (P0.05). There was also a significant decrease in the protein expression level of TGF-β1 and Smad3 (P<0.05). However, the expression of Smad7 protein was substantially increased when compared with the control group (P<0.05). It was concluded that the inhibition of TGFβ/Smad pathway in HSC-T6 cells by MG132 can reduce the production of profibrosis factors (TGFβ1, Smad3) and promote the expression of anti-fibrosis factor (Smad7), suggesting that MG132 may become a potential therapeutic alternative for liver fibrosis.