The activation of mTOR is required for monocyte pro-inflammatory response in patients with coronary artery disease

Clin Sci (Lond). 2015 Apr;128(8):517-26. doi: 10.1042/CS20140427.

Abstract

Nuclear factor-κB (NF-κB) is a key regulator of systematic inflammation in atherosclerosis (AS). The mammalian target of rapamycin (mTOR), a serine/threonine protein kinase, has emerged as an important regulator of chronic inflammation. However, the relationship between mTOR and NF-κB remains poorly defined. The aim of the present study was to investigate the role of mTOR in the pro-inflammatory pathway of human monocytes (HMCs) in patients with coronary artery disease (CAD) and to determine the interaction between mTOR and NF-κB signalling in the inflammatory state. HMCs were isolated from fasting blood samples of 68 patients with CAD and 59 subjects without CAD (non-CAD) to test the activity of NF-κB, p65 nuclear translocation and mTOR phosphorylation, which were all significantly elevated in the CAD group compared with those in the non-CAD group. The concentrations of serum interleukin (IL)-6 and tumour necrosis factor (TNF)-α were higher in the CAD group than in the non-CAD group. In an in vitro experiment, HMCs isolated from non-CAD subjects were used as culture model and were treated with sera extracted from CAD patients (CAD sera) or non-CAD subjects (con sera). CAD sera induced time-dependent phosphorylation of mTOR, aberrant NF-κB activation, as well as up-regulation of inflammatory factors. Moreover, inhibition of mTOR by pharmacological or genetic means abolished the CAD sera-triggered NF-κB activation and pro-inflammatory response. Furthermore, lipid-lowering drug statins partly blocked the CAD sera-activated mTOR and pro-inflammatory response. Our results show that CAD patients are in the pro-inflammatory state with increased NF-κB binding activity and enhanced mTOR phosphorylation. We also found that the activation of mTOR is required for the pro-inflammatory response via NF-κB-dependent pathway in HMCs, which unveils the underlying mechanism of AS and potential strategies to attenuate AS in clinical practice.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Coronary Artery Disease / blood
  • Coronary Artery Disease / drug therapy
  • Coronary Artery Disease / enzymology*
  • Coronary Artery Disease / pathology*
  • Enzyme Activation / drug effects
  • Female
  • Gene Knockdown Techniques
  • Humans
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / pharmacology
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / therapeutic use
  • Inflammation / metabolism*
  • Inflammation / pathology*
  • Inflammation Mediators / metabolism
  • Lipoproteins, LDL / metabolism
  • Male
  • Middle Aged
  • Monocytes / enzymology*
  • Monocytes / pathology*
  • NF-kappa B / metabolism
  • Phosphorylation / drug effects
  • Phosphoserine / metabolism
  • Protein Binding / drug effects
  • Signal Transduction / drug effects
  • TOR Serine-Threonine Kinases / metabolism*
  • Time Factors

Substances

  • Hydroxymethylglutaryl-CoA Reductase Inhibitors
  • Inflammation Mediators
  • Lipoproteins, LDL
  • NF-kappa B
  • oxidized low density lipoprotein
  • Phosphoserine
  • MTOR protein, human
  • TOR Serine-Threonine Kinases