Branched-chain amino acids prevent hepatic fibrosis and development of hepatocellular carcinoma in a non-alcoholic steatohepatitis mouse model

// Kai Takegoshi 1 , Masao Honda 1, 2 , Hikari Okada 1 , Riuta Takabatake 1 , Naoto Matsuzawa-Nagata 3 , Jean S. Campbell 4 , Masashi Nishikawa 1 , Tetsuro Shimakami 1 , Takayoshi Shirasaki 1 , Yoshio Sakai 1 , Taro Yamashita 1 , Toshinari Takamura 3 , Takuji Tanaka 5 , Shuichi Kaneko 1, 3 1 Department of Gastroenterology, Kanazawa University Graduate School of Medicine, Kanazawa, Japan 2 Department of Advanced Medical Technology, Kanazawa University Graduate School of Health Medicine, Kanazawa, Japan 3 Department of Disease Control and Homeostasis, Kanazawa University Graduate School of Medicine, Kanazawa, Japan 4 Department of Pathology, University of Washington School of Medicine, Seattle, WA, USA 5 The Tohkai Cytopathology Institute: Cancer Research and Prevention, Gifu, Japan Correspondence to: Masao Honda, email: mhonda@m-kanazawa.jp Keywords: branched-chain amino acids, nonalcoholic steatohepatitis, mammalian target of rapamycin complex 1, hepatocellular carcinoma, transforming growth factor β1 Received: May 12, 2016 Accepted: December 27, 2016 Published: February 13, 2017 ABSTRACT Oral supplementation with branched-chain amino acids (BCAA; leucine, isoleucine, and valine) in patients with liver cirrhosis potentially suppresses the incidence of hepatocellular carcinoma (HCC) and improves event-free survival. However, the detailed mechanisms of BCAA action have not been fully elucidated. BCAA were administered to atherogenic and high-fat (Ath+HF) diet-induced nonalcoholic steatohepatitis (NASH) model mice. Liver histology, tumor incidence, and gene expression profiles were evaluated. Ath+HF diet mice developed hepatic tumors at a high frequency at 68 weeks. BCAA supplementation significantly improved hepatic steatosis, inflammation, fibrosis, and tumors in Ath+HF mice at 68 weeks. GeneChip analysis demonstrated the significant resolution of pro-fibrotic gene expression by BCAA supplementation. The anti-fibrotic effect of BCAA was confirmed further using platelet-derived growth factor C transgenic mice, which develop hepatic fibrosis and tumors. In vitro, BCAA restored the transforming growth factor (TGF)-β1-stimulated expression of pro-fibrotic genes in hepatic stellate cells (HSC). In hepatocytes, BCAA restored TGF-β1-induced apoptosis, lipogenesis, and Wnt/β-Catenin signaling, and inhibited the transformation of WB-F344 rat liver epithelial stem-like cells. BCAA repressed the promoter activity of TGFβ1R1 by inhibiting the expression of the transcription factor NFY and histone acetyltransferase p300. Interestingly, the inhibitory effect of BCAA on TGF-β1 signaling was mTORC1 activity-dependent, suggesting the presence of negative feedback regulation from mTORC1 to TGF-β1 signaling. Thus, BCAA induce an anti-fibrotic effect in HSC, prevent apoptosis in hepatocytes, and decrease the incidence of HCC; therefore, BCAA supplementation would be beneficial for patients with advanced liver fibrosis with a high risk of HCC.