TNF-α stimulates endothelial palmitic acid transcytosis and promotes insulin resistance

Sci Rep. 2017 Mar 17:7:44659. doi: 10.1038/srep44659.

Abstract

Persistent elevation of plasma TNF-α is a marker of low grade systemic inflammation. Palmitic acid (PA) is the most abundant type of saturated fatty acid in human body. PA is bound with albumin in plasma and could not pass through endothelial barrier freely. Albumin-bound PA has to be transported across monolayer endothelial cells through intracellular transcytosis, but not intercellular diffusion. In the present study, we discovered that TNF-α might stimulate PA transcytosis across cardiac microvascular endothelial cells, which further impaired the insulin-stimulated glucose uptake by cardiomyocytes and promoted insulin resistance. In this process, TNF-α-stimulated endothelial autophagy and NF-κB signaling crosstalk with each other and orchestrate the whole event, ultimately result in increased expression of fatty acid transporter protein 4 (FATP4) in endothelial cells and mediate the increased PA transcytosis across microvascular endothelial cells. Hopefully the present study discovered a novel missing link between low grade systemic inflammation and insulin resistance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy / drug effects
  • Endothelial Cells / drug effects
  • Endothelial Cells / metabolism
  • Fatty Acid Transport Proteins / metabolism
  • Insulin Resistance*
  • Male
  • Mice
  • Microvessels / pathology
  • Models, Biological
  • Myocardium / pathology
  • Myocytes, Cardiac / drug effects
  • Myocytes, Cardiac / metabolism
  • NF-kappa B / metabolism
  • Palmitic Acid / metabolism*
  • Protein Kinase C / antagonists & inhibitors
  • Protein Kinase C / metabolism
  • Protein Kinase Inhibitors / pharmacology
  • RNA, Small Interfering / metabolism
  • Rats, Sprague-Dawley
  • Signal Transduction / drug effects
  • Transcytosis / drug effects*
  • Tumor Necrosis Factor-alpha / pharmacology*

Substances

  • Fatty Acid Transport Proteins
  • NF-kappa B
  • Protein Kinase Inhibitors
  • RNA, Small Interfering
  • Slc27a4 protein, mouse
  • Tumor Necrosis Factor-alpha
  • Palmitic Acid
  • Protein Kinase C