CD36/Sirtuin 1 Axis Impairment Contributes to Hepatic Steatosis in ACE2-Deficient Mice

Oxid Med Cell Longev. 2016:2016:6487509. doi: 10.1155/2016/6487509. Epub 2016 Dec 22.

Abstract

Background and Aims. Angiotensin converting enzyme 2 (ACE2) is an important component of the renin-angiotensin system. Since angiotensin peptides have been shown to be involved in hepatic steatosis, we aimed to evaluate the hepatic lipid profile in ACE2-deficient (ACE2-/y) mice. Methods. Male C57BL/6 and ACE2-/y mice were analyzed at the age of 3 and 6 months for alterations in the lipid profiles of plasma, faeces, and liver and for hepatic steatosis. Results. ACE2-/y mice showed lower body weight and white adipose tissue at all ages investigated. Moreover, these mice had lower levels of cholesterol, triglycerides, and nonesterified fatty acids in plasma. Strikingly, ACE2-/y mice showed high deposition of lipids in the liver. Expression of CD36, a protein involved in the uptake of triglycerides in liver, was increased in ACE2-/y mice. Concurrently, these mice exhibited an increase in hepatic oxidative stress, evidenced by increased lipid peroxidation and expression of uncoupling protein 2, and downregulation of sirtuin 1. ACE2-/y mice also showed impairments in glucose metabolism and insulin signaling in the liver. Conclusions. Deletion of ACE2 causes CD36/sirtuin 1 axis impairment and thereby interferes with lipid homeostasis, leading to lipodystrophy and steatosis.

MeSH terms

  • Angiotensin-Converting Enzyme 2
  • Animals
  • Body Weight
  • CD36 Antigens / genetics
  • CD36 Antigens / metabolism*
  • Catalase / metabolism
  • Cholesterol / blood
  • Down-Regulation
  • Fatty Acids, Nonesterified / blood
  • Fatty Liver / etiology
  • Fatty Liver / metabolism
  • Gluconeogenesis
  • Insulin / metabolism
  • Lipid Peroxidation
  • Liver / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Peptidyl-Dipeptidase A / deficiency
  • Peptidyl-Dipeptidase A / genetics*
  • RNA, Messenger / metabolism
  • Signal Transduction
  • Sirtuin 1 / metabolism*
  • Superoxide Dismutase / metabolism
  • Triglycerides / blood

Substances

  • CD36 Antigens
  • Fatty Acids, Nonesterified
  • Insulin
  • RNA, Messenger
  • Triglycerides
  • Cholesterol
  • Catalase
  • Superoxide Dismutase
  • Peptidyl-Dipeptidase A
  • Ace2 protein, mouse
  • Angiotensin-Converting Enzyme 2
  • Sirtuin 1