A collagen enhancer-promoter construct in transgenic mice is markedly stimulated by ethanol administration

Japanese herbal medicine Inchin-ko-to as a therapeutic drug for liver fibrosis

BACKGROUND/AIMS

Inchin-ko-to (TJ-135) is an herbal medicine used in Japan for treatment of icteric patients with cirrhosis. Its efficacy as an anti-fibrogenic drug was evaluated in relation to stellate cell activation.

METHODS/RESULTS

Liver fibrosis was induced in rats by repeated injections of carbon tetrachloride (CCl4) or pig-serum. Oral administration of TJ-135 improved the mortality of rats given CCl4 with reduced extents of liver necrosis and fibrosis. Similar improvement of liver fibrosis was found in rats given pig-serum showing no liver necrosis. DNA synthesis of stellate cells activated in vitro after isolation from normal rat liver was decreased by culture with TJ-135 in a dose-related manner, accompanied by decreased smooth muscle alpha actin expression and contractility. Such attenuation was not found in the cells cultured with geniposide, an iridoid compound of TJ-135, but genipin, an aglycone of geniposide formed in the gut by action of bacterial flora, markedly decreased stellate cell activation without affecting synthesis of proteins other than collagen.

CONCLUSIONS

TJ-135 may be useful for treatment of liver fibrosis and portal hypertension through suppression of activated hepatic stellate cell function by genipin, an absorbed form of its component.

Acute ethanol exposure attenuates expression of junD in human neuroblastoma cells

This study describes the effects of acute ethanol exposure on the mRNA levels of c-jun,junB and junD in the human neuroblastoma SH-SY5Y cell line. An acute exposure to 100 mM ethanol did not influence the basal and phorbol ester-induced expression of c-jun and junB, whereas the basal mRNA level of junD was attenuated by 30%. This effect was dose- and time-dependent with maximal inhibition being detected 2 h after 100 mM ethanol treatment and the mRNA levels gradually returned towards normal afterwards. Ethanol also inhibited phorbol ester-induced expression of junD. The fact that ethanol did not influence degradation of the junD mRNA suggests that acute ethanol suppresses the transcription of the gene. These results indicate that acute ethanol exerts different effects on expression of Jun transcription factors, suggesting that as compared to c-jun and junB, the junD gene may be more sensitive to acute ethanol treatment in neuronal cells.

Effects of ethanol on gene expression in rat bone: transient dose-dependent changes in mRNA levels for matrix proteins, skeletal growth factors, and cytokines are followed by reductions in bone formation

Several studies were performed in female rats to determine dose and time course changes in mRNA levels for matrix proteins in bone after a single administration of ethanol. As expected, dose-dependent transient increases in blood ethanol were measured. Additionally, there was mild hypocalcemia with no change in immunoreactive parathyroid hormone. Coordinated dose-dependent increases in mRNA for type 1 collagen, osteonectin, and osteocalcin were noted in the proximal tibial metaphysis 6 hr after ethanol was given, with the peak values occurring at a dose of 1.2 g/kg (0.4 ml). Similar increases in mRNA levels for matrix proteins were noted in lumbar vertebrae after ethanol treatment. The changes were specific for bone; ethanol had no effect on mRNA levels for matrix proteins in the uterus or liver, although the mRNA concentrations tended to be reduced in uterus. Message levels for several cytokines implicated in the regulation of bone turnover were also assayed; mRNA levels for transforming growth factor-beta1, transforming growth factor-beta2, interferon-gamma, and interleukin-6 were unchanged at doses ranging from 0.14 to 1.7 g/kg. At the highest dose of ethanol, the mRNA level for tumor necrosis factor-alpha was elevated while the level for insulin-like growth factor-1 was reduced. The time course effects of ethanol (0.4 ml dose) were determined in a separate experiment. Ethanol resulted in a transient increase in mRNA levels for the three bone matrix proteins assayed. However, matrix protein synthesis, as determined by incorporation of 3H-proline into the proximal tibial metaphysis, was not changed after 6 hr. The changes in mRNA levels for the matrix proteins were preceded by brief, transient decreases in mRNA levels for interleukin-1beta, interferon-gamma, and migration inhibitory factor, and followed by a more prolonged decrease in the mRNA level for insulin-like growth factor-1. A subsequent study was performed to determine the effects of repetitive daily treatment with ethanol on rat bone. After 7 days, there were highly significant decreases in the mRNA level for type 1 collagen, as well as decreased bone formation. These results suggest that ethanol may alter bone metabolism by disturbing signal transduction pathways that regulate the expression of genes for bone matrix proteins, skeletal growth factors, and cytokines.

Activation of Proalpha2(I) collagen promoter during hepatic fibrogenesis in transgenic mice

We previously identified the promoter sequence that is essential for basal and TGF-beta-stimulated transcription of alpha2(I) collagen gene (COL1A2). In the present study, we examined whether the promoter is activated during hepatic fibrogenesis by utilizing transgenic mice harboring the COL1A2 upstream sequence. Intraperitoneal CCl4 administration activated the -17 kb COL1A2 promoter more than 10-fold, whereas partial hepatectomy resulted in no significant change in the promoter activity. The non-parenchymal cell fraction, but not parenchymal hepatocytes, isolated from mice harboring the -313 COL1A2 promoter linked to a beta-galactosidase reporter gene contained large amounts of beta-galactosidase and endogenous COL1A2 mRNAs. beta-galactosidase activity in the cells from CCl4-treated mice was significantly higher than in those from untreated animals. These results indicated that different molecular mechanisms control COL1A2 transcription in CCl4-induced liver injury/fibrosis and physiological regeneration after partial hepatectomy, and that the -313 COL1A2 promoter is activated in a cell type-specific manner during hepatic fibrogenesis.