Saturated long-chain fatty acids activate inflammatory signaling in astrocytes
Version of Record online: 6 FEB 2012
© 2012 The Authors. Journal of Neurochemistry © 2012 International Society for Neurochemistry
Journal of Neurochemistry
Volume 120, Issue 6, pages 1060–1071, March 2012
How to Cite
Gupta, S., Knight, A. G., Gupta, S., Keller, J. N. and Bruce-Keller, A. J. (2012), Saturated long-chain fatty acids activate inflammatory signaling in astrocytes. Journal of Neurochemistry, 120: 1060–1071. doi: 10.1111/j.1471-4159.2012.07660.x
- Issue online: 6 MAR 2012
- Version of Record online: 6 FEB 2012
- Accepted manuscript online: 16 JAN 2012 10:10PM EST
- Received December 16, 2011; revised manuscript received January 8, 2012; accepted January 11, 2012.
- brain inflammation;
- reactive gliosis
J. Neurochem. (2012) 120, 1060–1071.
This study describes the effects of long-chain fatty acids on inflammatory signaling in cultured astrocytes. Data show that the saturated fatty acid palmitic acid, as well as lauric acid and stearic acid, trigger the release of TNFα and IL-6 from astrocytes. Unsaturated fatty acids were unable to induce cytokine release from cultured astrocytes. Furthermore, the effects of palmitic acid on cytokine release require Toll-like receptor 4 rather than CD36 or Toll-like receptor 2, and do not depend on palmitic acid metabolism to palmitoyl-CoA. Inhibitor studies revealed that pharmacologic inhibition of p38 or p42/44 MAPK pathways prevents the pro-inflammatory effects of palmitic acid, whereas JNK and PI3K inhibition does not affect cytokine release. Depletion of microglia from primary astrocyte cultures using the lysosomotropic agent l-leucine methyl ester revealed that the ability of palmitic acid to trigger cytokine release is not dependent on the presence of microglia. Finally, data show that the essential ω-3 fatty acid docosahexaenoic acid acts in a dose-dependent manner to prevent the actions of palmitic acid on inflammatory signaling in astrocytes. Collectively, these data demonstrate the ability of saturated fatty acids to induce astrocyte inflammation in vitro. These data thus raise the possibility that high levels of circulating saturated fatty acids could cause reactive gliosis and brain inflammation in vivo, and could potentially participate in the reported adverse neurologic consequences of obesity and metabolic syndrome.