Tetrandrine Regulates Hepatic Fibrosis And Cryptotanshinone Ameliorates Fulminant Hepatic Failure Via TAK1-MAPK And NF-κB Signaling

In current study we investigated anti-fibrogenic molecular mechanism of tetrandrine on T-HSC/CI-6 cells and hepatoprotective mechanism of cryptotanshinone on D-galactosamine (GalN)/lipopolysaccharide (LPS)-induced fulminant hepatic failure.(1) Tetrandrine is a bisbenzylisoquinoline alkaloid found from the Chinese herb, Stephania tetrandra. In the present study, we investigated the anti-fibrotic mechanism of tetrandrine on an immortalized rat hepatic stellate cells line, T-HSC/CI-6. T-HSC/CI-6 cells were treated with various concentrations of tetrandrine for indicated time in the absence or presence of TNF-α (10 ng/ml). Meanwhile tetrandrine was also treated on Chang liver cells, which was considered as normal human hepatocyte cell line. Tetrandrine (0.39-50 μM) dose- and time-dependently inhibited T-HSC/CI-6 cells viability in within 24 h, while tetrandrine displayed little toxicity on human Chang liver cells up to 25 μM. Tetrandrine time- and concentration-dependently increased the activation of caspase -3 and the cleavage of PARP. tetrandrine induced typical apoptosis on T-HSC/CI-6 cells confirmed by flow-cytometric analysis. Tetrandrine markedly induced α-SMA in a time- and concentration-dependent manner. Tetrandrine of 25 μM induced a significant increase in the phosphorylated levels of JNK, ERK and TAK1, nuclear translocation of NF-κB and IκB-α degradation as well. In addition, TNF-α caused slight cytotoxity on T-HSC/CI-6 cells, while tetrandrine exhibited cytotoxity up to 12.5 μM presence with TNF-a. a-SMA expression on TNF-α-treated cells was increasing time-dependently, meanwhile pretreated with 6.25 μM tetrandrine prior to TNF-α could reduce the increasing a-SMA protein expression time-dependently, as well as TRADD protein expression. TAK1 and JNK phosphorylations occurred by TNF-α, and 6.25 μM tetrandrine attenuated all these phosphorylations. Furthermore,6.25 μM tetrandrine reduced nuclear phosphorylated NF-κB p65 and NF-κB p65, while cytosolic IκBa and NF-κB p65 levels increased. In conclusion, anti-firogenic mechanisms of tetrandrine at least involved apoptosis-dependent and -independent pathwaya according to the concentration. With a high concentration, tetrandrine triggered HSCs apoptosis via activating NF-κB translocation and TAK1/JNK/ERK phosphorylation, conversely, with a low concentration tetrandrine prohibited TNF-a-stimulated NF-κB translocation and TAK1/JNK phosphorylation likely without induction of HSCs apoptosis.(2) Cryptotanshinone from Salvia miltiorrhiza Bunge was investigated for hepatoprotective effects in GalN/LPS-induced fulminant hepatic failure. Cryptotanshinone (20 or 40 mg/kg) was orally administered 12 and 1 h prior to GaIN (700 mg/kg)/LPS (10 μg/kg) injection. The increased mortality, serum aminotransferase activity and TNF-a levels by GalN/LPS were declined by cryptotanshinone pretreatment. In addition, cryptotanshinone attenuated GalN/LPS-induced apoptosis, characterized by the blockade of caspase-3,-8, and -9 activation, as well as the release of cytochrome c from the mitochondria. In addition, cryptotanshinone significantly suppressed JNK, ERK and p38 phosphorylation induced by GalN/LPS, and phosphorylation of TAK1 as well. Furthermore, cryptotanshinone significantly inhibited the activation of NF-κB and suppressed the production of proinflammatory cytokines. These findings suggested that hepatoprotective effect of cryptotanshinone is likely associated with its anti-apoptotic activity and the down-regulation of MAPKs and NF-κB associated at least in part with suppressing TAK1 phosphorylation.Our present data will contribute to development of effective and safe therapeutic agent for the treatment of fulminant hepatic failure and liver fibrosis.