Milica Bozic1, Carla Guzmán2, Marta Benet2, Sonia Sánchez-Campos3, Carmelo García-Monzón4, Eloi Gari5, Sonia Gatius6, José Manuel Valdivielso7, Ramiro Jover8. 1. Experimental Nephrology Laboratory, IRBLLEIDA, Lleida, Spain. 2. Experimental Hepatology Unit, IIS Hospital La Fe, Valencia, Spain. 3. Institute of Biomedicine (IBIOMED), University of León, Spain; CIBERehd, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Spain. 4. Liver Research Unit, Hospital Santa Cristina, IIS Princesa, Madrid, Spain; CIBERehd, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Spain. 5. Dep. Ciències Mèdiques Bàsiques, Universitat de Lleida, Spain. 6. Department of Pathology and Molecular Genetics, HUAV, IRBLLEIDA, Lleida, Spain. 7. Experimental Nephrology Laboratory, IRBLLEIDA, Lleida, Spain. Electronic address: valdivielso@medicina.udl.es. 8. Experimental Hepatology Unit, IIS Hospital La Fe, Valencia, Spain; CIBERehd, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Spain; Dep. Biochemistry and Molecular Biology, University of Valencia, Spain. Electronic address: ramiro.jover@uv.es.
Abstract
BACKGROUND & AIMS: The pathogenesis and progression of non-alcoholic fatty liver disease (NAFLD) is still incompletely understood. Several nuclear receptors play a role in liver lipid metabolism and can promote hepatosteatosis, but the possible role of vitamin D receptor (VDR) in NAFLD has not been investigated. METHODS: The expression of liver VDR was investigated in apolipoprotein E knockout (apoE(-/-)) mice on a high fat diet, in wild-type mice on methionine and choline deficient diet and in NAFLD patients with hepatosteatosis and non-alcoholic steatohepatitis. The relevance of VDR was assessed in apoE(-/-) mice by deletion of VDR or paricalcitol treatment and in human HepG2 cells by VDR transfection or silencing. The role of VDR in fibrosis was also determined in VDR knockout mice (VDR(-/-)) treated with thioacetamide. RESULTS: Expression of liver VDR was markedly induced in two mouse models of NAFLD, as well as in patients with hepatosteatosis, but decreased in non-alcoholic steatohepatitis. VDR deletion in high fat diet-fed apoE(-/-) mice protected against fatty liver, dyslipidemia and insulin resistance, and caused a decrease in taurine-conjugated bile acids, but did not influence fibrosis by thioacetamide. apoE(-/-)VDR(-/-) mouse livers showed decreased gene expression of CD36, DGAT2, C/EBPα and FGF21, and increased expression of PNPLA2, LIPIN1 and PGC1α. Treatment of apoE(-/-) mice on high fat diet with paricalcitol had modest opposite effects on steatosis and gene expression. Finally, this set of genes showed concordant responses when VDR was overexpressed or silenced in HepG2 cells. CONCLUSIONS: Induced hepatocyte VDR in NAFLD regulates key hepatic lipid metabolism genes and promotes high fat diet-associated liver steatosis. Therapeutic inhibition of liver VDR may reverse steatosis in early NAFLD. LAY SUMMARY: The amount of vitamin D receptor is induced early in the livers of mice and humans when they develop non-alcoholic fatty liver disease. If the gene for the vitamin D receptor is deleted, hepatic lipid metabolism changes and mice do not accumulate fat in the liver. We conclude that the vitamin D receptor can contribute to the fatty liver disease promoted by a high fat diet.
BACKGROUND & AIMS: The pathogenesis and progression of non-alcoholic fatty liver disease (NAFLD) is still incompletely understood. Several nuclear receptors play a role in liver lipid metabolism and can promote hepatosteatosis, but the possible role of vitamin D receptor (VDR) in NAFLD has not been investigated. METHODS: The expression of liver VDR was investigated in apolipoprotein E knockout (apoE(-/-)) mice on a high fat diet, in wild-type mice on methionine and choline deficient diet and in NAFLD patients with hepatosteatosis and non-alcoholic steatohepatitis. The relevance of VDR was assessed in apoE(-/-) mice by deletion of VDR or paricalcitol treatment and in human HepG2 cells by VDR transfection or silencing. The role of VDR in fibrosis was also determined in VDR knockout mice (VDR(-/-)) treated with thioacetamide. RESULTS: Expression of liver VDR was markedly induced in two mouse models of NAFLD, as well as in patients with hepatosteatosis, but decreased in non-alcoholic steatohepatitis. VDR deletion in high fat diet-fed apoE(-/-) mice protected against fatty liver, dyslipidemia and insulin resistance, and caused a decrease in taurine-conjugated bile acids, but did not influence fibrosis by thioacetamide. apoE(-/-)VDR(-/-) mouse livers showed decreased gene expression of CD36, DGAT2, C/EBPα and FGF21, and increased expression of PNPLA2, LIPIN1 and PGC1α. Treatment of apoE(-/-) mice on high fat diet with paricalcitol had modest opposite effects on steatosis and gene expression. Finally, this set of genes showed concordant responses when VDR was overexpressed or silenced in HepG2 cells. CONCLUSIONS: Induced hepatocyte VDR in NAFLD regulates key hepatic lipid metabolism genes and promotes high fat diet-associated liver steatosis. Therapeutic inhibition of liver VDR may reverse steatosis in early NAFLD. LAY SUMMARY: The amount of vitamin D receptor is induced early in the livers of mice and humans when they develop non-alcoholic fatty liver disease. If the gene for the vitamin D receptor is deleted, hepatic lipid metabolism changes and mice do not accumulate fat in the liver. We conclude that the vitamin D receptor can contribute to the fatty liver disease promoted by a high fat diet.
Authors: Ting Chen; Fahu Yuan; Hualin Wang; Yu Tian; Lei He; Yang Shao; Na Li; Zhiguo Liu Journal: Biomed Res Int Date: 2016-08-24 Impact factor: 3.411
Authors: Nasser M Al-Daghri; Abdul Khader Mohammed; Omar S Al-Attas; Mohammed Ghouse Ahmed Ansari; Kaiser Wani; Syed D Hussain; Shaun Sabico; Gyanendra Tripathi; Majed S Alokail Journal: Sci Rep Date: 2017-08-15 Impact factor: 4.379
Authors: Milica Bozic; Maite Caus; Raul R Rodrigues-Diez; Neus Pedraza; Marta Ruiz-Ortega; Eloi Garí; Pilar Gallel; Maria José Panadés; Ana Martinez; Elvira Fernández; José Manuel Valdivielso Journal: Nat Commun Date: 2020-04-23 Impact factor: 14.919