title: Monoterpene phenolic compound thymol promotes browning of 3T3-L1 adipocytes.
abstract: OBJECTIVE
  Appearance of brown-like adipocytes within white adipose tissue depots (browning) is associated with improved metabolic phenotypes, and thus a wide variety of dietary agents that contribute to browning of white adipocytes are being studied. The aim of this study was to assess the browning effect of thymol, a dietary monoterpene phenolic compound, in 3T3-L1 white adipocytes.
  
  
  METHODS
  Thymol-induced fat browning was investigated by determining expression levels of brown fat-specific genes and proteins by real-time RT-PCR and immunoblot analysis, respectively. Moreover, the molecular mechanism underlying the fat-browning effect of thymol was investigated by determining expression levels of key players responsible for browning in the presence of kinase inhibitors.
  
  
  RESULTS
  Thymol promoted mitochondrial biogenesis and enhanced expression of a core set of brown fat-specific markers as well as increased protein levels of PPARγ, PPARδ, pAMPK, pACC, HSL, PLIN, CPT1, ACO, PGC-1α, and UCP1, suggesting its possible role in browning of white adipocytes, augmentation of lipolysis, fat oxidation, and thermogenesis, and reduction of lipogenesis. Increased expression of UCP1 and other brown fat-specific markers by thymol was tightly coordinated with activation of β3-AR as well as AMPK, PKA, and p38 MAPK.
  
  
  CONCLUSIONS
  Our findings suggest that 3T3-L1 is a potential cell model for screening browning agents. Thymol plays multiple modulatory roles in the form of inducing the brown-like phenotype as well as enhancing lipid metabolism. Thus, thymol may be explored as a potentially promising food additive for prevention of obesity.
authors.affiliation: Department of Biotechnology, Daegu University, Kyungsan, Kyungbuk, 712-714, Republic of Korea.
authors.forename: Jae Heon
authors.initials: JH
authors.lastname: Choi
authors.affiliation: Department of Biotechnology, Daegu University, Kyungsan, Kyungbuk, 712-714, Republic of Korea.
authors.forename: Sang Woo
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Department of Food Science and Nutrition, University of Ulsan, Ulsan, Republic of Korea.
authors.forename: Rina
authors.initials: R
authors.lastname: Yu
authors.affiliation: Department of Biotechnology, Daegu University, Kyungsan, Kyungbuk, 712-714, Republic of Korea. jwyun@daegu.ac.kr.
authors.forename: Jong Won
authors.initials: JW
authors.lastname: Yun
mesh_terms: D041721:3T3-L1 Cells; D055372:AMP-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D017667:Adipocytes / Q000187:drug effects*; D052437:Adipocytes, Brown / Q000187:drug effects; D000818:Animals; D019735:Carbon-Carbon Ligases / Q000235:genetics / Q000378:metabolism; D002334:Carnitine O-Palmitoyltransferase / Q000235:genetics / Q000378:metabolism; D005819:Genetic Markers; D008066:Lipolysis / Q000187:drug effects; D051379:Mice; D039821:Monoterpenes / Q000494:pharmacology*; D047494:PPAR delta / Q000235:genetics / Q000378:metabolism; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D002787:Sterol Esterase / Q000235:genetics / Q000378:metabolism; D022722:Thermogenesis / Q000187:drug effects; D013943:Thymol / Q000494:pharmacology*; D000071256:Uncoupling Protein 1 / Q000235:genetics / Q000378:metabolism
chemical_list: D005819:Genetic Markers; D039821:Monoterpenes; D047494:PPAR delta; D047495:PPAR gamma; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C485290:Ppargc1a protein, mouse; C000604372:Ucp1 protein, mouse; D000071256:Uncoupling Protein 1; D013943:Thymol; D002334:Carnitine O-Palmitoyltransferase; D055372:AMP-Activated Protein Kinases; D002787:Sterol Esterase; D019735:Carbon-Carbon Ligases; C018757:acyl-CoA carboxylase
keywords: Adipocyte browning; Anti-obesity; Non-shivering thermogenesis; Thymol; UCP1