Xiaojun Liu1, Yong Gao2, Meixia Li3, Chao Geng2, Haifeng Xu4, Yaoguo Yang5, Yongjun Guo6, Tao Jiao2, Fude Fang7, Yongsheng Chang8. 1. National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences & School of Basic Medicine Peking Union Medical College, Beijing 100005, China. Electronic address: xiaojunliu@ibms.pumc.edu.cn. 2. National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences & School of Basic Medicine Peking Union Medical College, Beijing 100005, China. 3. State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China. 4. Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Interventional Therapy, Peking University Cancer Hospital & Institute, Beijing 100142, China. 5. The Department of Vascular Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China. 6. The Department of Clinical Laboratory, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China. 7. National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences & School of Basic Medicine Peking Union Medical College, Beijing 100005, China. Electronic address: fangfd@vip.sina.com. 8. National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences & School of Basic Medicine Peking Union Medical College, Beijing 100005, China. Electronic address: changy@ibms.pumc.edu.cn.
Abstract
BACKGROUND & AIMS: Heme oxygenase 1 (HO-1)-mediated increases in adiponectin, ameliorate the deleterious effects of obesity and metabolic syndrome; however, the effect of HO-1 on hepatic lipid metabolism remains elusive. The aim of this study is to evaluate the role of HO-1 in hepatic lipid metabolism. METHODS: Functional studies were performed using C57BL/6J (WT) mice and Sirt1 liver specific mutant (Sirt1-deficient) mice. The molecular mechanism was explored in primary hepatocytes and mouse liver. RESULTS: Chronic exposure to high-fat diet (HFD) induced hepatic steatosis in WT mice. Treatment of WT mice on HFD with cobalt protoporphyrin (CoPP), an inducer of HO-1 activity, decreased body weight and visceral fat content, reduced intracellular hepatic triglyceride and serum total cholesterol concentrations, and decreased liver lipid droplet formation. Compared with WT mice, the administration of CoPP to Sirt1-deficient mice on HFD increased visceral fat content, and slightly promoted liver lipid droplet formation. CoPP improved glucose tolerance and insulin sensitivity in WT mice on HFD, but compromised insulin sensitivity in Sirt1-deficient mice on HFD. Furthermore, CoPP-induced Sirt1 expression and decreased sterol regulatory element binding protein 1c (SREBP-1c) expression in WT mice on HFD. However, CoPP promoted SREBP-1c expression in Sirt1-deficient hepatocytes, which was reversed by a protein tyrosine phosphatase 1b inhibitor. Additionally, while the administration of CoPP to WT mice on HFD improved antioxidant and anti-inflammatory states, these CoPP-mediated effects were abolished in Sirt1-deficient mice. CONCLUSIONS: Sirt1 mediates the effect of CoPP on ameliorating liver metabolic damage caused by HFD.
BACKGROUND & AIMS:Heme oxygenase 1 (HO-1)-mediated increases in adiponectin, ameliorate the deleterious effects of obesity and metabolic syndrome; however, the effect of HO-1 on hepatic lipid metabolism remains elusive. The aim of this study is to evaluate the role of HO-1 in hepatic lipid metabolism. METHODS: Functional studies were performed using C57BL/6J (WT) mice and Sirt1 liver specific mutant (Sirt1-deficient) mice. The molecular mechanism was explored in primary hepatocytes and mouse liver. RESULTS: Chronic exposure to high-fat diet (HFD) induced hepatic steatosis in WT mice. Treatment of WT mice on HFD with cobalt protoporphyrin (CoPP), an inducer of HO-1 activity, decreased body weight and visceral fat content, reduced intracellular hepatic triglyceride and serum total cholesterol concentrations, and decreased liver lipid droplet formation. Compared with WT mice, the administration of CoPP to Sirt1-deficientmice on HFD increased visceral fat content, and slightly promoted liver lipid droplet formation. CoPP improved glucose tolerance and insulin sensitivity in WT mice on HFD, but compromised insulin sensitivity in Sirt1-deficientmice on HFD. Furthermore, CoPP-induced Sirt1 expression and decreased sterol regulatory element binding protein 1c (SREBP-1c) expression in WT mice on HFD. However, CoPP promoted SREBP-1c expression in Sirt1-deficient hepatocytes, which was reversed by a protein tyrosine phosphatase 1b inhibitor. Additionally, while the administration of CoPP to WT mice on HFD improved antioxidant and anti-inflammatory states, these CoPP-mediated effects were abolished in Sirt1-deficientmice. CONCLUSIONS:Sirt1 mediates the effect of CoPP on ameliorating liver metabolic damage caused by HFD.
Authors: Kojiro Nakamura; Shoichi Kageyama; Shi Yue; Jing Huang; Takehiro Fujii; Bibo Ke; Rebecca A Sosa; Elaine F Reed; Nakul Datta; Ali Zarrinpar; Ronald W Busuttil; Jerzy W Kupiec-Weglinski Journal: Am J Transplant Date: 2017-12-18 Impact factor: 8.086
Authors: Jonathan R Brestoff; Tim Brodsky; Alexandra Z Sosinsky; Ryan McLoughlin; Elena Stansky; Leila Fussell; Aaron Sheppard; Maria DiSanto-Rose; Erin E Kershaw; Thomas H Reynolds Journal: PLoS One Date: 2015-09-23 Impact factor: 3.240