me3738 and Liver-Failure

We examined whether the 22beta-methoxyolean-12-ene-3beta,24(4beta)-diol (ME3738)-mediated selective induction of interleukin-6 increased alpha1-acid glycoprotein and serum amyloid A expression, and whether these proteins protected against liver injury in vitro and in vivo. ME3738 treatment in male mice increased gene expression of alpha1-acid glycoprotein subtypes and serum amyloid A 2 genes, and plasma concentration of serum amyloid A. Treatment with alpha1-acid glycoprotein at 5 mg/animal or serum amyloid A at 0.03 and 0.1 mg/animal prior to concanavalin A administration reduced multifocal necrosis in the liver. Treatment with alpha1-acid glycoprotein and serum amyloid A, but not alpha1-antitrypsin, protected Hep G2 cells against cell injury. These results suggest that alpha1-acid glycoprotein and serum amyloid A, increased by ME3738-induced interleukin-6, might protect against concanavalin A-induced liver injury.

Topics: Aflatoxin B1; Animals; Concanavalin A; Gene Expression Regulation; Interleukin-6; Liver Failure; Male; Mice; Mice, Inbred BALB C; Oleanolic Acid; Oligonucleotide Array Sequence Analysis; Orosomucoid; RNA, Messenger; Serum Amyloid A Protein

ME3738 is a new compound that attenuates liver disease in several models of acute and chronic liver inflammation. We used the concanavalin A (Con A) model to elucidate the molecular mechanisms of ME3738 to block liver cell damage. Pretreatment of BALB/c mice with ME3738 prior to Con A injection resulted in a significant reduction in liver injury. The protective effect of ME3738 prior to Con A injection was associated with a reduction in IL-6 serum levels and NF-kappaB DNA binding in liver nuclear extracts. However, STAT3 DNA binding was induced via ME3738 prior to Con A injection. Further analysis showed that ME3738 induces IL-6 serum levels and activates STAT3 DNA binding and target gene transcription. The relevance of this finding was assessed in IL-6(-/-) mice. In these animals, ME3738 induced no increase in IL-6 serum expression, and activation of IL-6-dependent pathways was not found. In addition, ME3738 did not protect IL-6(-/-) animals from Con A-induced liver failure, while IL-6 injection was still effective. Therefore, we demonstrate that ME3738 triggers IL-6 expression, which activates pathways that are relevant to protect from Con A-induced liver failure.

Topics: Acute-Phase Reaction; Animals; Concanavalin A; DNA-Binding Proteins; Gene Expression; Immunosuppressive Agents; Interleukin-6; Liver Failure; Male; Mice; Mice, Inbred BALB C; Mice, Knockout; NF-kappa B; Oleanolic Acid; STAT3 Transcription Factor; Trans-Activators; Tumor Necrosis Factor-alpha