Hepatocyte FoxO1 Deficiency Protects From Liver Fibrosis via Reducing Inflammation and TGF-ß1-mediated HSC Activation.

BACKGROUND & AIMS: The O-class of the forkhead transcription factor FoxO1 is a crucial factor mediating insulin→PI3K→Akt signaling and governs diverse cellular processes. However, the role of hepatocyte FoxO1 in liver fibrosis has not been well-established. In his study, we investigated the role of hepatocyte FoxO1 in liver fibrosis and uncovered the underlying mechanisms. METHODS: Liver fibrosis was established by carbon tetrachloride (CCL4) administration and compared between liver-specific deletion of FoxO1 deletion (F1KO) and control (CNTR) mice. Using genetic and bioinformatic strategies in vitro and in vivo, the role of hepatic FoxO1 in liver fibrosis and associated mechanisms was established. RESULTS: Increased FoxO1 expression and FoxO1 signaling activation were observed in CCL4-induced fibrosis. Hepatic FoxO1 deletion largely attenuated CCL4-induced liver injury and fibrosis compared with CNTR mice. F1KO mice showed ameliorated CCL4-induced hepatic inflammation and decreased TGF-ß1 mRNA and protein levels compared with those of CNTR mice. In primary hepatocytes, FoxO1 deficiency reduced TGF-ß1 expression and secretion. Conditioned medium (CM) collected from wild-type hepatocytes treated with CCL4 activated human HSC cell line (LX-2); such effect was attenuated by FoxO1 deletion in primary hepatocytes or neutralization of TGF-ß1 in the CM using TGF-ß1 antibody. Hepatic FoxO1 overexpression in CNTR mice promoted CCL4-induced HSC activation; such effect was blocked in L-TGF-ß1KO mice. CONCLUSIONS: Hepatic FoxO1 mediates CCL4-inducled liver fibrosis via upregulating hepatocyte TGF-ß1 expression, stimulating hepatic inflammation and TGF-ß1-mediated HSC activation. Hepatic FoxO1 may be a therapeutic target for prevention and treatment of liver fibrosis.

Liver knockout YAP gene improved insulin resistance-induced hepatic fibrosis.

Yes-associated protein (YAP), as a co-activator of transcription factors, is a downstream protein in the Hippo signaling pathway with important functions in cell proliferation, apoptosis, invasion and migration. YAP also plays a key role in the development of CCl4-induced liver fibrosis. However, the mechanism of YAP during hepatic fibrosis progression and reversion is still unclear. Mild liver fibrosis was developed after 4 months of high-fat diet (HFD) stimulation, and we found that the YAP signaling pathway was activated. Here, we aim to reveal whether specific knockout of Yap gene in the liver can improve liver fibrosis induced by insulin resistance (IR) stimulated by HFD, and further explain its specific mechanism. We found that liver-specific Yap gene knockout improved IR-induced liver fibrosis and liver dysfunction, and this mechanism is related to the inhibition of the insulin signal pathway at the FoxO1 level. These findings provide a new insight, and Yap is expected to be a new target to reverse the early stage of liver fibrosis induced by IR.

Baihe Wuyao decoction ameliorates CCl4-induced chronic liver injury and liver fibrosis in mice through blocking TGF-ß1/Smad2/3 signaling, anti-inflammation and anti-oxidation effects.

ETHNOPHARMACOLOGICAL RELEVANCE: Baihe Wuyao decoction (BWD), a prescription of Traditional Chinese Medicines, composed of Lilium brownii var. viridulum Baker.(Lilii Bulbus) and Lindera aggregata (Sims) Kosterm. (Linderae Radix), has been used to treat epigastric pain and superficial gastritis for hundreds of years in China. Recently, some compounds obtained from Lilii Bulbus and Linderae Radix had active effects of hepatic protection or liver fibrosis alleviation. Thus, we aim to evaluate the effects of BWD on treatment of chronic liver injury and liver fibrosis induced by carbon tetrachloride (CCl4) and to elucidate the possible molecular mechanism. MATERIALS AND METHODS: Mice were treated with BWD (low, medium and high dose), diammonium glycyrrhizinate or vehicle by oral gavage once daily, simultaneously intraperitoneal injected with a single dose of CCl4 (1 µl/g body weight) twice a week for consecutive 6 weeks. Next, all mice were sacrificed after fasted 12 h, and serums and liver tissues were harvested for analysis. The hepatic injury was detected by serum biomarker assay, including aspartate aminotransferase (AST) and alanine aminotransferase (ALT). The hepatic histology and collagen were illustrated by hematoxylin-eosin staining and Sirius red staining respectively. The antioxidant capacity of liver tissues was evaluated by the contents of superoxide dismutase (SOD) and malondialdehyde (MDA) in liver homogenization. The mRNA gene or protein expressions related to fibrosis, oxidative stress and inflammation molecules were performed by real-time quantitative PCR (RT-PCR) or Western-blot. RESULTS: BWD exhibited a good hepatic protection with ameliorating liver histological changes, decreasing serum AST and ALT contents, and reducing hepatic fibrosis with stimulation ECMs (such as Collagen1 and Collagen3) degradation. BWD inhibited hepatic stellate cells (HSCs) activation, promoted matrix metalloproteinase-2 (MMP2), MMP9, and MMP12 while suppressing tissue inhibitors of matrix metalloproteinase-1 (TIMP1) expression, and blocked traditional fibrosis TGF-ß1/Smad2/3 signal pathway. Moreover, BWD exhibited anti-inflammation effect proved by the reduction of liver Interleukin-1ß (IL-1ß), TNF-α, IL-11 mRNA levels and promoted anti-oxidation effects determined by inhibition of liver MDA and iNOS levels while promoting liver SOD and Mn-SOD. CONCLUSION: BWD ameliorates CCl4-induced CLI and liver fibrosis which is correlated to its blocking TGF-ß1/Smad2/3 signaling, anti-inflammation, and anti-oxidation effects. BWD, as a small traditional prescription, is a promising treatment for CLI and liver fibrosis through multiple pharmacological targets.