title: A critical role for ChREBP-mediated FGF21 secretion in hepatic fructose metabolism.
abstract: Increased fructose consumption is a contributor to the burgeoning epidemic of non-alcoholic fatty liver disease (NAFLD). Recent evidence indicates that the metabolic hormone FGF21 is regulated by fructose consumption in humans and rodents and may play a functional role in this nutritional context. Here, we sought to define the mechanism by which fructose ingestion regulates FGF21 and determine whether FGF21 contributes to an adaptive metabolic response to fructose consumption.
  
  
  
  We tested the role of the transcription factor carbohydrate responsive-element binding protein (ChREBP) in fructose-mediated regulation of FGF21 using ChREBP knockout mice. Using FGF21 knockout mice, we investigated whether FGF21 has a metabolic function in the context of fructose consumption. Additionally, we tested whether a ChREBP-FGF21 interaction is likely conserved in human subjects.
  
  
  
  Hepatic expression ofChREBP-βandFgf21acutely increased 2-fold and 3-fold, respectively, following fructose gavage, and this was accompanied by increased circulating FGF21. The acute increase in circulating FGF21 following fructose gavage was absent in ChREBP knockout mice. Induction ofChREBP-βand its glycolytic, fructolytic, and lipogenic gene targets were attenuated in FGF21 knockout mice fed high-fructose diets, and this was accompanied by a 50% reduction in de novo lipogenesis a, 30% reduction VLDL secretion, and a 25% reduction in liver fat compared to fructose-fed controls. In human subjects, serum FGF21 correlates with de novo lipogenic rates measured by stable isotopic tracers (R = 0.55, P = 0.04) consistent with conservation of a ChREBP-FGF21 interaction. After 8 weeks of high-fructose diet, livers from FGF21 knockout mice demonstrate atrophy and fibrosis accompanied by molecular markers of inflammation and stellate cell activation; whereas, this did not occur in controls.
  
  
  
  In summary, ChREBP and FGF21 constitute a signaling axis likely conserved in humans that mediates an essential adaptive response to fructose ingestion that may participate in the pathogenesis of NAFLD and liver fibrosis.
authors.affiliation: Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA.
authors.forename: Ffolliott M
authors.initials: FM
authors.lastname: Fisher
authors.affiliation: Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA.
authors.forename: MiSung
authors.initials: M
authors.lastname: Kim
authors.affiliation: Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA.
authors.forename: Ludivine
authors.initials: L
authors.lastname: Doridot
authors.affiliation: Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA.
authors.forename: Jeremy C
authors.initials: JC
authors.lastname: Cunniff
authors.affiliation: The Rogosin Institute and Departments of Medicine and Biochemistry, Weill Cornell Medical College, New York, NY, 10021, USA.
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Parker
authors.affiliation: The Rogosin Institute and Departments of Medicine and Biochemistry, Weill Cornell Medical College, New York, NY, 10021, USA.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Levine
authors.affiliation: Department of Nutritional Sciences & Toxicology, University of California at Berkeley, Berkeley, CA, 94702, USA.
authors.forename: Marc K
authors.initials: MK
authors.lastname: Hellerstein
authors.affiliation: The Rogosin Institute and Departments of Medicine and Biochemistry, Weill Cornell Medical College, New York, NY, 10021, USA.
authors.forename: Lisa C
authors.initials: LC
authors.lastname: Hudgins
authors.affiliation: Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA. Electronic address: emaratos@bidmc.harvard.edu.
authors.forename: Eleftheria
authors.initials: E
authors.lastname: Maratos-Flier
authors.affiliation: Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA. Electronic address: mark.herman@duke.edu.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Herman
mesh_terms: D000818:Animals; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000378:metabolism*; D005260:Female; D005346:Fibroblast Growth Factors / Q000097:blood / Q000378:metabolism*; D005632:Fructose / Q000008:administration & dosage / Q000378:metabolism*; D006019:Glycolysis; D022781:Hepatocytes / Q000378:metabolism; D006801:Humans; D050155:Lipogenesis; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D065626:Non-alcoholic Fatty Liver Disease / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; C116385:MLXIPL protein, human; C506001:Mlxipl protein, mouse; D009687:Nuclear Proteins; D014157:Transcription Factors; C414620:fibroblast growth factor 21; D005632:Fructose; D005346:Fibroblast Growth Factors
keywords: ChREBP; FGF21; Fructose; Lipogenesis; NAFLD