Transcriptional programming of lipid and amino acid metabolism by the skeletal muscle circadian clock

PLoS Biol. 2018 Aug 10;16(8):e2005886. doi: 10.1371/journal.pbio.2005886. eCollection 2018 Aug.

Abstract

Circadian clocks are fundamental physiological regulators of energy homeostasis, but direct transcriptional targets of the muscle clock machinery are unknown. To understand how the muscle clock directs rhythmic metabolism, we determined genome-wide binding of the master clock regulators brain and muscle ARNT-like protein 1 (BMAL1) and REV-ERBα in murine muscles. Integrating occupancy with 24-hr gene expression and metabolomics after muscle-specific loss of BMAL1 and REV-ERBα, here we unravel novel molecular mechanisms connecting muscle clock function to daily cycles of lipid and protein metabolism. Validating BMAL1 and REV-ERBα targets using luciferase assays and in vivo rescue, we demonstrate how a major role of the muscle clock is to promote diurnal cycles of neutral lipid storage while coordinately inhibiting lipid and protein catabolism prior to awakening. This occurs by BMAL1-dependent activation of Dgat2 and REV-ERBα-dependent repression of major targets involved in lipid metabolism and protein turnover (MuRF-1, Atrogin-1). Accordingly, muscle-specific loss of BMAL1 is associated with metabolic inefficiency, impaired muscle triglyceride biosynthesis, and accumulation of bioactive lipids and amino acids. Taken together, our data provide a comprehensive overview of how genomic binding of BMAL1 and REV-ERBα is related to temporal changes in gene expression and metabolite fluctuations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ARNTL Transcription Factors / physiology*
  • Amino Acids / metabolism
  • Amino Acids / physiology
  • Animals
  • CLOCK Proteins / genetics
  • Circadian Clocks / physiology*
  • Circadian Rhythm / genetics
  • Gene Expression
  • Homeostasis
  • Humans
  • Lipid Metabolism / physiology
  • Lipids
  • Mice
  • Mice, Knockout
  • Muscle, Skeletal / physiology*
  • RNA, Messenger / metabolism

Substances

  • ARNTL Transcription Factors
  • BMAL1 protein, human
  • Amino Acids
  • Lipids
  • RNA, Messenger
  • CLOCK Proteins

Grants and funding

Emmy Noether grant (DFG) (grant number UH275/1-1). NHU. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. European Commission (Integrated Project MYOAGE) (grant number 223576). SS. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Telethon Italy Grant (grant number GGP13222). LS. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Fondazione CARIPARO, Padova. LS. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.