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Background and Aim: Hepatic fibrosis is a worldwide healthy burden associated with significant morbidity and mortality. It is caused by a variety of chronic liver injuries. There is currently no effective treatment for liver fibrosis. In this report, we tested an imidazolium salt, 1,3-diisopropylimidazolium tetrafluoroborate (DPIM), for its anti-fibrotic properties in the thioacetamide-induced mouse model., Methods: DPIM was orally delivered to the thioacetamide-treated mice via drinking water for 12 weeks at the onset of thioacetamide treatment at a concentration of 0.1% (prevention group), and for 4 weeks starting at the 8(th) week at a concentration of 0.1% or 0.2% (attenuation group), respectively. Messenger RNA and protein were determined by real-time polymerase chain reaction and Western blotting, matrix metalloproteinase (MMP) activities were measured by fluorogenic peptide substrate and zymography. Mitogen-activated protein kinase (MAPK) and PI3K inhibitors were applied in HSC-T6 cells in combination of DPIM to probe possible signal pathways underlying the compound's action., Results: We observed a significant reduction in collagen deposition in both prevention and attenuation groups. The α-smooth muscle actin (SMA) and transforming growth factor (TGF)-β gene expressions were also reduced in both groups. The reduction of collagen deposition could be in part attributed to the suppression of CCR-2 expression and the enhanced matrix protein remodeling by metalloproteinases, especially MMP-3. MAPK and PI3K signaling pathways may be partially participated in DPIM's molecular action., Conclusion: DPIM reduced fibrosis in the thioacetamide-induced mouse liver fibrosis model, and warranted further studies for possible clinical application in the future., (© 2012 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.)

Aim: To understand which and how different miRNAs are implicated in the process of hepatic stellate cell (HSC) activation., Methods: We used microarrays to examine the differential expression of miRNAs during in vitro activation of primary HSCs (pHSCs). The transcriptome changes upon stable transfection of rno-miR-146a into an HSC cell line were studied using cDNA microarrays. Selected differentially regulated miRNAs were investigated by quantitative real-time polymerase chain reaction during in vivo HSC activation. The effect of miRNA mimics and inhibitor on the in vitro activation of pHSCs was also evaluated., Results: We found that 16 miRNAs were upregulated and 26 were downregulated significantly in 10-d in vitro activated pHSCs in comparison to quiescent pHSCs. Overexpression of rno-miR-146a was characterized by marked upregulation of tissue inhibitor of metalloproteinase-3, which is implicated in the regulation of tumor necrosis factor-α activity. Differences in the regulation of selected miRNAs were observed comparing in vitro and in vivo HSC activation. Treatment with miR-26a and 29a mimics, and miR-214 inhibitor during in vitro activation of pHSCs induced significant downregulation of collagen type I transcription., Conclusion: Our results emphasize the different regulation of miRNAs in in vitro and in vivo activated pHSCs. We also showed that miR-26a, 29a and 214 are involved in the regulation of collagen type I mRNA.

Intercellular communication is an important tool used by the cells to effectively regulate concerted responses. Hepatic stellate cells (HSCs) communicate to each other through functional gap junctions composed of connexin 43 (Cx43) proteins. We show that exogenous human TGF-beta1 (hTGF-beta1), a pro-fibrotic stimulus, decreases Cx43 mRNA and protein in a rat HSC cell line and primary HSCs. Furthermore, hTGF-beta1 increases the phosphorylation of Cx43 at serine 368. These effects lead to a decrease in the gap junction intercellular communication between the HSCs, as shown by gap-FRAP analysis. We also observe the binding of Snai1, from the nuclear extract of HSCs, to a Snai1 consensus sequence in the Cx43 promoter. In the same context, Snai1 siRNA transfection results in an up-regulation of Cx43 suggesting that TGF-beta1 may regulate Cx43 via Snai1. In addition, we demonstrate that the knockdown of Cx43 by siRNA transfection results in a slower proliferation of HSCs. These findings illuminate a new effect of TGF-beta1 in HSCs, namely the regulation of intercellular communication by affecting the expression level and the phosphorylation state of Cx43 through Snai1 signaling.

A class of imidazolium salts (IMSs) is routinely used in organic synthetic chemistry as precursors to generate N-heterocyclic carbenes (NHCs) with catalytic activity. However, their biological properties are largely unknown. The current study investigates the biological activity of a typical NHC precursor DBZIM and its trimer TDBZIM in hepatic stellate cells (HSCs), which is an in vitro model for studying liver fibrosis. The results show that HSCs treated with IMSs have an enhanced GSH/GSSG ratio and a reduced level of reactive oxygen species (ROS), which may consequently contribute to the attenuation in gene expression of fibrogenic molecules such as smooth muscle actin-alpha (SMAA), transforming growth factor-beta 1 (TGF-beta1), procollagen alphaI(I) and fibronectin. Further, the in vivo experiments demonstrate that DBZIM is an anti-fibrotic agent in a mouse model of liver fibrosis. These findings suggest that the versatile IMSs could be a potential source for developing novel therapeutics to treat liver fibrosis and other fibrogenic disorders caused by oxidative stress and TGF-beta1 mal-signalling.