Korean J Gastroenterol.  2007 Mar;49(3):139-146.

Probiotics may Reduce Inflammation by Enhancing Peroxisome Proliferator Activated Receptor gamma Activation in HT-29 Cells

• Eun CS
• Han DS
• Lee SH
• Jeon YC
• Sohn JH
• Kim YS
• Lee J

Abstract

BACKGROUND/AIMS
The peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor highly expressed in the colon which plays an anti-inflammatory role through the inhibition of nuclear factor-kappaB (NF-kappaB) pathway. Probiotics have been shown to exert beneficial effects on inflammatory bowel diseases. However, the exact mechanism by which probiotics exert protection against intestinal inflammation is not well understood. The aims of this study were to evaluate the attenuation of inflammatory response by probiotics in intestinal epithelial cells and to study the association between probiotics and PPARgamma.
METHODS
HT-29 human epithelial cells were stimulated with LPS (20microgram/mL) and probiotics, Lactobacillus casei (L. casei) (10(5)-10(7) cfu/mL), or with LPS (20microgram/mL) alone for 24 hours. Interleukin-8 (IL-8), cyclooxygenase-2 (COX-2), toll-like receptor-4 (TLR-4) and PPARgamma mRNA expressions were assessed by RT-PCR. IL-8 protein secretion was measured by ELISA. HT-29 cells were transfected with tk promoter-luciferase plasmid containing a peroxisome proliferator response element (PPRE). After stimulation with L. casei or PPARgamma agonist (15d-PGJ2 or ciglitazone), luciferase activities were measured.
RESULTS
LPS induced IL-8, COX-2, TLR-4 mRNA expression, and IL-8 protein secretion in HT-29 cells. Treatment with LPS and L. casei in comparison with LPS stimulation alone lowered IL-8, COX-2, TLR-4 mRNA expression, and IL-8 protein secretion. L. casei increased PPARgamma mRNA expression in dose-dependent manner. L. casei activated PPRE in HT-29 cells transfected with PPRE3-tk-luciferase construct.
CONCLUSIONS
Probiotics, L. casei, suppresses the expression of inflammatory mediators in intestinal epithelial cells. The anti-inflammatory action of L. casei might be partially related to PPARgamma activation.

Keyword

Lactobacillus casei; PPARgamma; HT-29 cells

MeSH Terms

Cyclooxygenase 2/genetics/metabolism
Genetic Vectors
HT29 Cells
Humans
Inflammation Mediators/*metabolism
Interleukin-8/genetics/metabolism
Lactobacillus casei
Lipopolysaccharides/pharmacology
Luciferases/analysis/genetics
PPAR gamma/drug effects/*metabolism
Probiotics/*pharmacology
RNA, Messenger/metabolism
Reverse Transcriptase Polymerase Chain Reaction
Signal Transduction
Toll-Like Receptor 4/genetics/metabolism