title: Norepinephrine and rosiglitazone synergistically induce Elovl3 expression in brown adipocytes.
abstract: The Elovl3 gene, which putatively encodes for a protein involved in the elongation of saturated and monounsaturated fatty acids in the C20-C24 range, is expressed in murine liver, skin, and brown adipose tissue (BAT). In BAT, Elovl3 is dramatically upregulated during tissue activation in response to cold exposure, and functional data imply that ELOVL3 is a critical enzyme for lipid accumulation in brown adipocytes during the early phase of tissue recruitment. The activation of BAT is controlled by sympathetic nerve activity and norepinephrine release. By using primary cultures of brown adipocytes, we show here that the induced Elovl3 gene expression is synergistically regulated by norepinephrine and the peroxisome proliferator-activated receptor (PPAR) gamma ligand rosiglitazone. In addition, the potency of rosiglitazone to induce Elovl3 expression was several orders of magnitude higher than for the PPARalpha and PPARdelta ligands WY-14643 and L-165041, respectively. The maximal increase in mRNA level by norepinephrine and rosiglitazone is achieved by induced transcription as well as increased mRNA stability, and the whole process requires novel protein synthesis. We conclude that norepinehrine and PPARgamma, despite having different roles in brown adipocyte activation and differentiation, cooperate in expanding the intracellular lipid pool by synergistically stimulating Elovl3 expression.
authors.affiliation: The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-10691, Stockholm, Sweden.
authors.forename: Johanna A
authors.initials: JA
authors.lastname: Jörgensen
authors.forename: Damir
authors.initials: D
authors.lastname: Zadravec
authors.forename: Anders
authors.initials: A
authors.lastname: Jacobsson
mesh_terms: D000123:Acetyltransferases; D017667:Adipocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D002001:Adipose Tissue, Brown / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D004357:Drug Synergism; D000081031:Fatty Acid Elongases; D005786:Gene Expression Regulation / Q000187:drug effects; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D047495:PPAR gamma / Q000502:physiology*; D020025:Peroxisome Proliferators / Q000494:pharmacology*; D010642:Phenoxyacetates / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000077154:Rosiglitazone; D045162:Thiazolidinediones / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: C520164:4-(3-(2-propyl-3-hydroxy-4-acetyl)phenoxy)propyloxyphenoxy acetic acid; C000630960:Elovl3 protein, mouse; D008565:Membrane Proteins; D047495:PPAR gamma; D020025:Peroxisome Proliferators; D010642:Phenoxyacetates; D011500:Protein Synthesis Inhibitors; D011743:Pyrimidines; D012333:RNA, Messenger; D045162:Thiazolidinediones; D000077154:Rosiglitazone; D003609:Dactinomycin; C006253:pirinixic acid; D003513:Cycloheximide; D000123:Acetyltransferases; D000081031:Fatty Acid Elongases; D009638:Norepinephrine