Modulation of inflammatory cytokines and mitogen-activated protein kinases by acetate in primary astrocytes

J Neuroimmune Pharmacol. 2013 Mar;8(1):287-300. doi: 10.1007/s11481-012-9426-4. Epub 2012 Dec 12.

Abstract

Acetate supplementation attenuates neuroglia activation in a rat model of neuroinflammation by a mechanism associated with an increase in brain acetyl-CoA, an alteration in histone acetylation, and reduction of interleukin (IL)-1β expression. We propose that reduced astroglial activation occurs by disrupting astrocyte-derived inflammatory signaling and cytokine release. Using primary astroglial cultures, we found that LPS (0-25 ng/ml, 4 h) increased tumor necrosis factor (TNF-α) and IL-1β in a concentration-dependent manner, which was reduced by treatment with sodium acetate (12 mM). LPS did not alter H3K9 acetylation or IL-6 levels, whereas acetate treatment increased H3K9 acetylation by 2-fold and decreased basal levels of IL-6 by 2-fold. Acetate treatment attenuated the LPS-induced increase in TNF-α mRNA, but did not reverse the mRNA levels of other pro-inflammatory cytokines. By contrast, LPS decreased TGF-β1 and IL-4 protein and TGF-β1 mRNA, all of which was reversed with acetate treatment. Further, we found that acetate treatment completely reversed LPS-induced phosphorylation of MAPK p38 and decreased basal levels of phosphorylated extracellular signal-regulated kinases1/2 (ERK1/2) by 2-fold. Acetate treatment also reversed LPS-elevated NF-κB p65, CCAAT/enhancer-binding protein beta protein levels, and reduced basal levels of phosphorylated NF-κB p65 at serine 536. These results suggest that acetate treatment has a net anti-inflammatory effect in LPS-stimulated astrocytes that is largely associated with a disruption in MAPK and NF-κB signaling.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Acetates / pharmacology*
  • Acetyl Coenzyme A / metabolism
  • Acetylation
  • Animals
  • Astrocytes / drug effects
  • Astrocytes / metabolism*
  • Blotting, Western
  • CCAAT-Enhancer-Binding Proteins / genetics
  • CCAAT-Enhancer-Binding Proteins / metabolism
  • Cells, Cultured
  • Cytokines / metabolism*
  • Histones / metabolism
  • In Situ Nick-End Labeling
  • Inflammation / metabolism
  • Inflammation / pathology
  • L-Lactate Dehydrogenase / metabolism
  • Lipopolysaccharides / antagonists & inhibitors
  • Lipopolysaccharides / pharmacology
  • MAP Kinase Signaling System / drug effects
  • Mice
  • Mice, Inbred C57BL
  • Mitogen-Activated Protein Kinases / metabolism*
  • NF-kappa B / metabolism
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • Real-Time Polymerase Chain Reaction
  • Signal Transduction / drug effects
  • Signal Transduction / physiology

Substances

  • Acetates
  • CCAAT-Enhancer-Binding Proteins
  • Cytokines
  • Histones
  • Lipopolysaccharides
  • NF-kappa B
  • RNA, Messenger
  • Acetyl Coenzyme A
  • L-Lactate Dehydrogenase
  • Mitogen-Activated Protein Kinases