The development of cirrhosis requires changes in matrix composition and turnover as well as conspicuous changes in intrahepatic vasculature that require orchestrated Vismodegib cell line interaction between nonparenchymal liver cells, especially endothelial cells and stellate cells. These vascular changes significantly contribute to the morbid complication of portal hypertension that accompanies advanced

fibrosis. In this study, we focused on (1) identifying novel cellular and molecular pathways underlying angio-matrix changes that occur during liver fibrosis and (2) defining how sorafenib, a compound that shows promising clinical use in patients with cirrhosis and liver cancer, affects these pathways. In ICG-001 this regard, the present study reveals several

novel cellular and molecular phenomena that shed further light on angioarchitectural changes that accompany fibrosis (Fig. 8). First, we demonstrate that HSCs secrete Ang1, which behaves as a key contributor to fibrosis-associated vascular changes. We show that excessive HSC-derived Ang1 disrupts sinusoidal homeostasis by promoting increased wrapping interactions between HSCs and LECs as well as increased junctional connections among LECs. These phenomena culminate in a sinusoidal remodeling process that enhances HSC contraction around sinusoids as well as increased angiogenesis. Surprisingly, Ang1 production requires PI3K/Akt activation, though it is independent

of Raf, which is the classical target of sorafenib in hepatoma cells.4, 25 This finding demonstrates that sorafenib uses distinct pathways to exert its changes in epithelial versus mesenchymal cells. These vascular changes are also coordinated with matrix remodeling as shown by an increase in Raf-dependent fibronectin production, which like Ang1 production relies on integrity of the KLF6 transcriptional pathway, thus revealing a remarkable coordination of vascular and matrix changes that contribute to cirrhosis. Finally, we provide clear evidence that the multikinase inhibitor sorafenib inhibits the KLF6–Ang1–fibronectin molecular triad, thereby attenuating angioarchitectural changes that typify cirrhosis. These observations also suggest Leukotriene-A4 hydrolase that the function of sorafenib in cancer and cirrhosis might have distinct differences that can be exploited for tailoring different concentration responses that can achieve beneficial effects in the two conditions. However, it should be noted that therapies that target intrahepatic angiogenesis in human cirrhosis have not been evaluated in any systematic fashion, thus any beneficial or even harmful effect of such an intervention cannot be reliably predicted.2 To define nuclear events that regulate Ang1 expression, we examined the promoter of this gene for cis-regulatory sequences that can potentially bind to relevant transcription factors.