Transcriptional regulation of autophagy by an FXR-CREB axis

Nature. 2014 Dec 4;516(7529):108-11. doi: 10.1038/nature13949. Epub 2014 Nov 12.

Abstract

Lysosomal degradation of cytoplasmic components by autophagy is essential for cellular survival and homeostasis under nutrient-deprived conditions. Acute regulation of autophagy by nutrient-sensing kinases is well defined, but longer-term transcriptional regulation is relatively unknown. Here we show that the fed-state sensing nuclear receptor farnesoid X receptor (FXR) and the fasting transcriptional activator cAMP response element-binding protein (CREB) coordinately regulate the hepatic autophagy gene network. Pharmacological activation of FXR repressed many autophagy genes and inhibited autophagy even in fasted mice, and feeding-mediated inhibition of macroautophagy was attenuated in FXR-knockout mice. From mouse liver chromatin immunoprecipitation and high-throughput sequencing data, FXR and CREB binding peaks were detected at 178 and 112 genes, respectively, out of 230 autophagy-related genes, and 78 genes showed shared binding, mostly in their promoter regions. CREB promoted autophagic degradation of lipids, or lipophagy, under nutrient-deprived conditions, and FXR inhibited this response. Mechanistically, CREB upregulated autophagy genes, including Atg7, Ulk1 and Tfeb, by recruiting the coactivator CRTC2. After feeding or pharmacological activation, FXR trans-repressed these genes by disrupting the functional CREB-CRTC2 complex. This study identifies the new FXR-CREB axis as a key physiological switch regulating autophagy, resulting in sustained nutrient regulation of autophagy during feeding/fasting cycles.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy / genetics*
  • Cyclic AMP Response Element-Binding Protein / metabolism*
  • Fasting / physiology
  • Gene Expression Regulation* / drug effects
  • Isoxazoles / pharmacology
  • Liver / cytology
  • Liver / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Protein Binding
  • Receptors, Cytoplasmic and Nuclear / agonists
  • Receptors, Cytoplasmic and Nuclear / metabolism*

Substances

  • Cyclic AMP Response Element-Binding Protein
  • Isoxazoles
  • Receptors, Cytoplasmic and Nuclear
  • farnesoid X-activated receptor
  • GW 4064