Disturbances in the murine hepatic circadian clock in alcohol-induced hepatic steatosis

Sci Rep. 2014 Jan 16:4:3725. doi: 10.1038/srep03725.

Abstract

To investigate the role of the circadian clock in the development of alcohol-induced fatty liver disease we examined livers of mice chronically alcohol-fed over 4-weeks that resulted in steatosis. Here we show time-of-day specific changes in expression of clock genes and clock-controlled genes, including those associated with lipid and bile acid regulation. Such changes were not observed following a 1-week alcohol treatment with no hepatic lipid accumulation. Real-time bioluminescence reporting of PERIOD2 protein expression suggests that these changes occur independently of the suprachiasmatic nucleus pacemaker. Further, we find profound time-of-day specific changes to the rhythmic synthesis/accumulation of triglycerides, cholesterol and bile acid, and the NAD/NADH ratio, processes that are under clock control. These results highlight not only that the circadian timekeeping system is disturbed in the alcohol-induced hepatic steatosis state, but also that the effects of alcohol upon the clock itself may actually contribute to the development of hepatic steatosis.

Publication types

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

MeSH terms

  • Animals
  • Bile Acids and Salts / biosynthesis
  • Circadian Clocks* / genetics
  • Circadian Rhythm / genetics
  • Disease Models, Animal
  • Ethanol / administration & dosage
  • Fatty Liver, Alcoholic / etiology*
  • Fatty Liver, Alcoholic / metabolism
  • Gene Expression Profiling
  • Gene Expression Regulation / drug effects
  • Lipid Metabolism / genetics
  • Liver / drug effects
  • Liver / metabolism*
  • Liver / pathology*
  • Male
  • Mice
  • NAD / metabolism
  • Period Circadian Proteins / genetics
  • Period Circadian Proteins / metabolism

Substances

  • Bile Acids and Salts
  • Per2 protein, mouse
  • Period Circadian Proteins
  • NAD
  • Ethanol