Pituitary tumor transforming gene as a novel regulatory factor of liver fibrosis.

AIMS: Pituitary tumor-transforming gene (PTTG) is involved in multiple cellular pathways. We studied the development of liver fibrosis induced by thioacetamide (TAA) in knockout (PTTG-/-) and wildtype (PTTG+/+) mice. MAIN METHODS: Liver fibrosis in PTTG+/+ and PTTG-/- mice was induced by escalating dose TAA treatment (50-400mg/kg, i.p.) for 12 weeks and assessed by histochemistry, immunohistochemistry, liver hydroxyproline, serum fibrosis markers and fibrosis-related mRNA expression by real-time PCR determination. KEY FINDINGS: Both PTTG+/+ and PTTG-/- mice treated with TAA developed signs of fibrosis and inflammatory cell infiltration. However, histological signs of bridging fibrosis and connective tissue square morphometry were significantly attenuated in mice lacking PTTG. α-SMA immunohistochemistry revealed that hepatic stellate cell activation was markedly reduced in PTTG-/- mice compared to wildtype controls. Hepatic hydroxyproline levels were significantly lower in fibrotic PTTG-/- group. The serum TNFα and hepatic TNFα mRNA expression were significantly lower in fibrotic PTTG-/- animals, as well as hepatic TGFß and VEGF mRNA levels compared to TAA-treated wildtype controls. Serum hyaluronate and TGFß levels were markedly elevated in fibrotic mice of both genotypes, but were not altered by the absence of PTTG. SIGNIFICANCE: TAA-induced fibrosis development is significantly ameliorated in PTTG-/- mice. These animals demonstrated diminished stellate cell activation, suppressed circulating serum markers of inflammation, fibrogenesis and angiogenesis. The presented findings suggest that PTTG is functionally required for hepatic fibrosis progression in an animal model of chronic liver injury. PTTG can be considered as a new important target for prevention and treatment of liver fibrosis/cirrhosis.

N-Stearoylethanolamine suppresses the pro-inflammatory cytokines production by inhibition of NF-κB translocation.

N-Stearoylethanolamine (NSE) is a minor lipid that belongs to the N-Acylethanolamines family that mediates a wide range of biological processes. This study investigates the mechanisms of anti-inflammatory action of NSE on different model systems. Namely, we estimated the effect of NSE on inflammatory cytokines mRNA level (leukemia cells L1210), cytokines content (serum and LPS-stimulated macrophages) and nuclear translocation of NF-κB (peritoneal macrophages LPS-stimulated and isolated from rats with obesity-induced insulin resistance). The results indicated that NSE dose-dependently inhibits the IL-1 and IL-6 mRNA level in L1210 cells. Furthermore, the NSE treatment triggered a normalization of serum TNF-α level in insulin resistant rats and a reduction of medium IL-1 level in LPS-activated peritoneal macrophages. These NSE's effects were associated with the inhibition of nuclear NF-κB translocation in rat peritoneal macrophages.

Correlation between generation of nitric oxide and cell viability in human peripheral blood mononuclear cells and leukemic Jurkat T-cell line.

AIM: To measure nitric oxide (NO) production in the form of nitrite derivative in relation to cell viability and apoptosis development in human peripheral blood mononuclear cells compared to that processes in human leukemic Jurkat T-cell line. METHODS: Apoptosis was induced by dexamethasone (1 microg/ml) or NaNO(2) (7 microg/ml) added in the presence or absence of NO-synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) (27 microg/ml) during cell culturing. Cell viability was determined by trypan blue assay. Apoptosis was measured using DNA "ladder" assay. RESULTS: Dexamethazone and NaNO(2) were shown to cause DNA "laddering" in both cell types. L-NAME prevented the appearance of apoptosis in both normal mononuclear cells of peripheral blood and leukemic Jurkat T-cell in the case of dexamethasone action, but it could not prevent it in the case of NaNO(2) action. The results of cell viability showed that both the dexamethasone and NaNO(2) significantly increased the percentage of dead cells. Their effect was better expressed in Jurkat T-cell line. The levels of nitrite production were higher in the leukemic T-cells comparing to such levels in the normal mononuclear cells. CONCLUSION: Strong positive correlation was demonstrated between NO production and apoptosis development in both studied cell types, however leukemic Jurkat T-cell line responses were better expressed than such responses in normal mononuclear cells of peripheral blood. Potential significance of that correlation as well as possible mechanisms of appearing differences are discussed.