1,25-Dihydroxyvitamin D3 attenuates endotoxin-induced production of inflammatory mediators by inhibiting MAPK activation in primary cortical neuron-glia cultures

J Neuroinflammation. 2015 Aug 12;12:147. doi: 10.1186/s12974-015-0370-0.

Abstract

Background: Neuroinflammation occurs in insulted regions of the brain and may be due to reactive oxygen species (ROS), nitric oxide (NO), cytokines, and chemokines produced by activated glia. Excessive production of neurotoxic molecules causes further neuronal damage. Low levels of vitamin D3 are a risk factor for various brain diseases.

Methods: Using the bacterial endotoxin, lipopolysaccharide (LPS), to induce neuroinflammation in primary cortical neuron-glia cultures, we investigated how 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) affected neuroinflammation.

Results: LPS (100 ng/ml) induced the accumulation of nitrite and the production of ROS, interleukin (IL)-6, and macrophage inflammatory protein (MIP)-2 in time-dependent manners. Inhibition of p38 and extracellular signal-regulated kinase (ERK) but not c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) by 20 μM of SB203580, PD98059, and SP600125, significantly reduced LPS-induced ROS production, NO accumulation, and inducible NO synthase (iNOS) expression, respectively. LPS-induced IL-6 and MIP-2 were significantly attenuated by inhibition of p38, ERK, and JNK MAPK. Cotreatment with 1,25(OH)2D3 attenuated LPS-induced ROS production, NO accumulation, and iNOS expression in concentration-dependent manners. 1,25(OH)2D3 also reduced LPS-induced production of IL-6 and MIP-2. Similarly, iNOS, IL-6, and MIP-2 mRNA expression in cells treated with LPS significantly increased, whereas this effect was attenuated by 1,25(OH)2D3. Moreover, LPS-induced phosphorylation of p38, ERK, and JNK MAPK was significantly inhibited by 1,25(OH)2D3.

Conclusions: Our findings indicate that 1,25(OH)2D3 reduced the LPS-stimulated production of inflammatory molecules in neuron-glia cultures by inhibiting MAPK pathways and the production of downstream inflammatory molecules. We suggest that 1,25(OH)2D3 can be used to alleviate neuroinflammation in various brain injuries.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antioxidants / pharmacology
  • Calcitriol / pharmacology*
  • Cerebral Cortex / cytology
  • Cerebral Cortex / drug effects
  • Cerebral Cortex / enzymology*
  • Chemokine CXCL2 / metabolism
  • Enzyme Activation / drug effects
  • Inflammation Mediators / antagonists & inhibitors*
  • Inflammation Mediators / metabolism*
  • Interleukin-6 / biosynthesis
  • Lipopolysaccharides / antagonists & inhibitors*
  • Lipopolysaccharides / toxicity*
  • MAP Kinase Signaling System / drug effects
  • Mitogen-Activated Protein Kinases / metabolism*
  • Neuroglia / drug effects
  • Neuroglia / enzymology*
  • Neurons / drug effects
  • Neurons / enzymology*
  • Nitric Oxide Synthase Type II / antagonists & inhibitors
  • Primary Cell Culture
  • Rats
  • Rats, Sprague-Dawley
  • Reactive Oxygen Species / metabolism
  • Vitamins / pharmacology*

Substances

  • Antioxidants
  • Chemokine CXCL2
  • Inflammation Mediators
  • Interleukin-6
  • Lipopolysaccharides
  • Reactive Oxygen Species
  • Vitamins
  • Nitric Oxide Synthase Type II
  • Mitogen-Activated Protein Kinases
  • Calcitriol