High-fat and high-cholesterol diet decreases phosphorylated inositol-requiring kinase-1 and inhibits autophagy process in rat liver

Sci Rep. 2019 Aug 29;9(1):12514. doi: 10.1038/s41598-019-48973-w.

Abstract

Precise molecular pathways involved in the progression of non-alcoholic steatohepatitis (NASH) remain to be elucidated. As Mallory-Denk bodies were occasionally observed in the enlarged hepatocytes in NASH model rat (SHRSP5/Dmcr) fed high-fat and high-cholesterol (HFC) diet, we aimed to clarify the roles of autophagy and endoplasmic reticulum (ER) stress in NASH progression. Male SHRSP5/Dmcr were randomly divided into 4 groups. Two groups were fed a control diet; the other two groups were fed a HFC diet for 2 and 8 weeks, respectively. The HFC diet increased the autophagy-related proteins levels and microtubule-associated protein 1 light chain 3-II/I ratio after 2 and 8 weeks, respectively. However, regarding ER stress-related proteins, the HFC diet decreased the levels of phosphorylated (p-) inositol-requiring kinase-1 (p-IRE-1) and p-protein kinase RNA-like ER kinase after 2 weeks. Additionally, the HFC diet increased anti-ubiquitin-positive cells and the level of the autophagy substrate p62, suggesting that the HFC diet induced dysfunction in ubiquitin-dependent protein degradation pathways. In conclusion, the HFC diet arrested the autophagy process in the liver; this was particularly associated with decreases in p-IRE-1 expression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy*
  • Cholesterol, Dietary / adverse effects*
  • Cholesterol, Dietary / metabolism
  • Diet, High-Fat / adverse effects*
  • Disease Models, Animal
  • Endoplasmic Reticulum Stress
  • Endoribonucleases / genetics
  • Endoribonucleases / metabolism*
  • Humans
  • Liver / enzymology
  • Liver / metabolism
  • Liver / physiopathology*
  • Male
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / metabolism
  • Multienzyme Complexes / genetics
  • Multienzyme Complexes / metabolism*
  • Non-alcoholic Fatty Liver Disease / etiology
  • Non-alcoholic Fatty Liver Disease / genetics
  • Non-alcoholic Fatty Liver Disease / metabolism*
  • Non-alcoholic Fatty Liver Disease / physiopathology
  • Phosphorylation
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism*
  • Rats

Substances

  • Cholesterol, Dietary
  • Ern1 protein, rat
  • LC3 protein, rat
  • Microtubule-Associated Proteins
  • Multienzyme Complexes
  • Protein Serine-Threonine Kinases
  • Endoribonucleases