title: Carnosic acid inhibits TLR4-MyD88 signaling pathway in LPS-stimulated 3T3-L1 adipocytes.
abstract: OBJECTIVE
  Carnosic acid (CA), found in rosemary (Rosemarinus officinalis) leaves, is known to exhibit anti-obesity and anti-inflammatory activities. However, whether its anti-inflammatory potency can contribute to the amelioration of obesity has not been elucidated. The aim of the current study was to investigate the effect of CA on Toll-like receptor 4 (TLR4) pathways in the presence of lipopolysaccharide (LPS) in 3T3-L1 adipocytes.
  
  
  METHODS
  3T3-L1 adipocytes were treated with CA (0-20 µM) for 1 h, followed by treatment with LPS for 30 min; mRNA expression of adipokines and protein expression of TLR4-related molecules were then measured.
  
  
  RESULTS
  LPS-stimulated 3T3-L1 adipocytes showed elevated mRNA expression of tumor necrosis factor (TNF)-α, interleukin-6, and monocyte chemoattractant protein-1, and CA significantly inhibited the expression of these adipokine genes. LPS-induced up regulation of TLR4, myeloid differentiation factor 88, TNF receptor-associated factor 6, and nuclear factor-κB, as well as phosphorylated extracellular receptor-activated kinase were also suppressed by pre-treatment of 3T3-L1 adipocytes with CA.
  
  
  CONCLUSIONS
  Results of this study suggest that CA directly inhibits TLR4-MyD88-dependent signaling pathways and decreases the inflammatory response in adipocytes.
authors.affiliation: Department of Food & Nutrition Education, Graduate School of Education, Soonchunhyang University, Asan, Chungnam 336-745, Korea.
authors.forename: Mi-Young
authors.initials: MY
authors.lastname: Park
authors.affiliation: Department of Obstetrics and Gynecology, Soonchunhyang University Cheonan Hospital, Soonchunhyang-6-gil 31, Dongnam-gu, Cheonan 330-721, Korea.
authors.forename: Seong Taek
authors.initials: ST
authors.lastname: Mun
keywords: 3T3-L1 adipocytes; carnosic acid; inflammation; toll-like receptor 4