Nanomolar Caffeic Acid Decreases Glucose Uptake and the Effects of High Glucose in Endothelial Cells

PLoS One. 2015 Nov 6;10(11):e0142421. doi: 10.1371/journal.pone.0142421. eCollection 2015.

Abstract

Epidemiological studies suggest that moderate and prolonged consumption of coffee is associated with a reduced risk of developing type 2 diabetes but the molecular mechanisms underlying this effect are not known. In this study, we report the effects of physiological concentrations of caffeic acid, easily achievable by normal dietary habits, in endothelial cells cultured in 25 mM of glucose (high glucose, HG). In HG, the presence of 10 nM caffeic acid was associated with a decrease of glucose uptake but not to changes of GLUT-1 membrane localization or mRNA levels. Moreover, caffeic acid countered HG-induced loss of barrier integrity, reducing actin rearrangement and FITC-dextran passage. The decreased flux of glucose associated to caffeic acid affected HG induced apoptosis by down-regulating the expression of initiator (caspase 8 and 9) and effector caspases (caspase 7 and 3) and by increasing the levels of phosphorylated Bcl-2. We also observed that caffeic acid in HG condition was associated to a reduction of p65 subunit nuclear levels with respect to HG alone. NF-κB activation has been shown to lead to apoptosis in HG treated cells and the analysis of the expression of a panel of about 90 genes related to NF-κB signaling pathway revealed that caffeic acid significantly influenced gene expression changes induced by HG. In conclusion, our results suggest that caffeic acid, decreasing the metabolic stress induced by HG, allows the activation of survival mechanisms mediated by a different modulation of NF-κB-related signaling pathways and to the activation of anti-apoptotic proteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / drug effects
  • Caffeic Acids / pharmacology*
  • Cell Line
  • Endothelial Cells / drug effects*
  • Endothelial Cells / metabolism
  • Glucose / metabolism*
  • Glucose Transporter Type 1 / genetics
  • Glucose Transporter Type 1 / metabolism
  • Human Umbilical Vein Endothelial Cells
  • Humans
  • NF-kappa B / metabolism
  • Permeability / drug effects
  • RNA, Messenger / metabolism

Substances

  • Caffeic Acids
  • Glucose Transporter Type 1
  • NF-kappa B
  • RNA, Messenger
  • SLC2A1 protein, human
  • Glucose
  • caffeic acid

Grants and funding

This work was supported by the Italian Ministry of Agricultural and Nutritional Policies and Forestry (Special Research Projects MiPAAF - NUME and MiPAAF - MEDITO). The authors are grateful to the Epigenomics Flagship Project—EPIGEN. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.