Inflammation

, Volume 33, Issue 1, pp 46–57

Gamma-Linolenic Acid Inhibits Inflammatory Responses by Regulating NF-κB and AP-1 Activation in Lipopolysaccharide-Induced RAW 264.7 Macrophages

  • Cheng-Sue Chang
  • Hai-Lun Sun
  • Chong-Kuei Lii
  • Haw-Wen Chen
  • Pei-Yin Chen
  • Kai-Li Liu
Article

DOI: 10.1007/s10753-009-9157-8

Cite this article as:
Chang, CS., Sun, HL., Lii, CK. et al. Inflammation (2010) 33: 46. doi:10.1007/s10753-009-9157-8

Abstract

Gamma linolenic acid (GLA) is a member of the n-6 family of polyunsaturated fatty acids and can be synthesized from linoleic acid (LA) by the enzyme delta-6-desaturase. The therapeutic values of GLA supplementation have been documented, but the molecular mechanism behind the action of GLA in health benefits is not clear. In this study, we assessed the effect of GLA with that of LA on lipopolysaccharide (LPS)-induced inflammatory responses and further explored the molecular mechanism underlying the pharmacological properties of GLA in mouse RAW 264.7 macrophages. GLA significantly inhibited LPS-induced protein expression of inducible nitric oxide synthase, pro-interleukin-1β, and cyclooxygenase-2 as well as nitric oxide production and the intracellular glutathione level. LA was less potent than GLA in inhibiting LPS-induced inflammatory mediators. Both GLA and LA treatments dramatically inhibited LPS-induced IκB-α degradation, IκB-α phosphorylation, and nuclear p65 protein expression. Moreover, LPS-induced nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) nuclear protein–DNA binding affinity and reporter gene activity were significantly decreased by LA and GLA. Exogenous addition of GLA but not LA significantly reduced LPS-induced expression of phosphorylated extracellular signal-regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase (JNK)-1. Our data suggest that GLA inhibits inflammatory responses through inactivation of NF-κB and AP-1 by suppressed oxidative stress and signal transduction pathway of ERK and JNK in LPS-induced RAW 264.7 macrophages.

KEY WORDS

gamma-linolenic acidinflammationlinoleic acidlipopolysaccharidesmouse RAW 264.7 macrophages

Abbreviations

AP-1

activator protein-1

COX-2

cyclooxygenase-2

EMSA

electrophoretic mobility shift assay

ERK1/2

extracellular signal-regulated kinase1/2

GAPDH

glyceraldehydes-3-phosphate dehydrogenase

GLA

gamma-linolenic acid

GSH

glutathione

IL-1β

interleukin-1β

iNOS

inducible form of NOS

IS

internal standard

JNK

c-Jun NH2-terminal kinase

LA

linoleic acid

LPS

lipopolysaccharide

MAPK

mitogen-activated protein kinase

MTT

3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide

NF-κB

nuclear factor-κB

NO

nitric oxide

NOS

nitric oxide synthase

PGE2

prostaglandin E2

PMSF

phenylmethylsulfonyl fluoride

rcRNA

recombinant RNA

RT-PCR

reverse transcriptase polymerase chain reaction

SEAP

secretory alkaline phosphatase

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Cheng-Sue Chang
    • 1
  • Hai-Lun Sun
    • 2
    • 3
  • Chong-Kuei Lii
    • 4
  • Haw-Wen Chen
    • 4
  • Pei-Yin Chen
    • 5
  • Kai-Li Liu
    • 5
    • 6
  1. 1.Department of NeurologyChanghua Christian HospitalChanghua CityTaiwan
  2. 2.Department of AllergyChung Shan Medical University HospitalTaichungTaiwan
  3. 3.School of MedicineChung Shan Medical UniversityTaichungTaiwan
  4. 4.Department of NutritionChina Medical UniversityTaichungTaiwan
  5. 5.Department of NutritionChung Shan Medical UniversityTaichungTaiwan
  6. 6.Department of DietitianChung Shan Medical University HospitalTaichungTaiwan