The role of IkappaBalpha in TNF-alpha-induced apoptosis in hepatic stellate cell line HSC-T6

Pentoxifylline inhibits liver fibrosis via hedgehog signaling pathway

Infection of schistosomiasis japonica may eventually lead to liver fibrosis, and no effective antifibrotic therapies are available but liver transplantation. Hedgehog (HH) signaling pathway has been involved in the process and is a promising target for treating liver fibrosis. This study aimed to explore the effects of pentoxifylline (PTX) on liver fibrosis induced by schistosoma japonicum infection by inhibiting the HH signaling pathway. Phorbol12-myristate13-acetate (PMA) was used to induce human acute mononuclear leukemia cells THP-1 to differentiate into macrophages. The THP-1-derived macrophages were stimulated by soluble egg antigen (SEA), and the culture supernatants were collected for detection of activation of macrophages. Cell Counting Kit-8 (CCK-8) was used to detect the cytotoxicity of the culture supernatant and PTX on the LX-2 cells. The LX-2 cells were administered with activated culture supernatant from macrophages and(or) PTX to detect the transforming growth factor-β gene expression. The mRNA expression of shh and gli-1, key parts in HH signaling pathway, was detected. The mRNA expression of shh and gli-1 was increased in LX-2 cells treated with activated macrophages-derived culture supernatant, suggesting HH signaling pathway may play a key role in the activation process of hepatic stellate cells (HSCs). The expression of these genes decreased in LX-2 cells co-cultured with both activated macrophages-derived culture supernatant and PTX, indicating PTX could suppress the activation process of HSCs. In conclusion, these data provide evidence that PTX prevents liver fibrogenesis in vitro by the suppression of HH signaling pathway.

Construction of COL1A1-shRNA expression plasmid and screening of effective sequences to inhibit COL1A1 expression

AIM: To construct and select procollagen type 1 alpha 1 (COL1A1) short hairpin RNA (shRNA) expression plasmid that can inhibit COL1A1 mRNA expression in rat hepatic stellate cell (HSC).

METHODS: Rat COL1A1 cDNA sequence was obtained from NCBI website. Three small interfering RNA sequences were selected through online design of the Whitehead Institute. The corresponding double-stranded DNA was used to construct pGPU6/GFP/Neo plasmids, namely pGPU6/GFP/Neo-shRNA-A, pGPU6/GFP/Neo-shRNA-B and pGPU6/GFP/Neo-shRNA-C. HSC-T6 cells were transfected with a green fluorescent protein (GFP)-labeled siRNA to assess the transfection efficiency. To get most effective and optimal dosage siRNA, the three plasmids (1, 2, 3, 4 μg) were transfected into HSC-T6 cells with Lipofectamine 2000 respectively, and the untreated HSC-T6 cells were used as controls. The expression of COL1A1 mRNA was detected by reverse transcription-polymerase chain reaction (RT-PCR) after the most effective and optimal dosage was used.

RESULTS: The expression plasmids targeting on COL1A1 mRNA were successfully constructed, and confirmed by agarose electrophoresis and sequence analysis. The transfection efficiencies at a dose of 1, 2, 3, and 4 μg were approximately 16.7%, 20.3%, 23.5%, and 22.3%, and 2 μg was considered as the most optimal dosage in each group. The inhibitory rates of COL1A1 mRNA levels in the HSC-T6 cells transfected with pGPU6/GFP/Neo-shRNA-A, pGPU6/GFP/Neo-shRNA-B, and pGPU6/GFP/Neo-shRNA-C were 16.6%, 63.3%, and 80.3%, respectively, when 2 μg siRNA plasmid was used.

CONCLUSION: The constructed expression plasmid pGPU6/GFP/Neo-shRNA-C can effectively inhibit the expression of COL1A1 mRNA, providing a new method and material for the treatment of liver fibrosis.