Artificial Sweeteners Stimulate Adipogenesis and Suppress Lipolysis Independently of Sweet Taste Receptors

Becky R. Simon, Sebastian D. Parlee, Brian S. Learman, Hiroyuki Mori, Erica L. Scheller, William P. Cawthorn, Xiaomin Ning, Katherine Gallagher, Bjoern Tyrberg, Fariba M. Assadi-Porter, Charles R. Evans, Ormond A. MacDougald*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

G protein-coupled receptors mediate responses to a myriad of ligands, some of which regulate adipocyte differentiation and metabolism. The sweet taste receptors T1R2 and T1R3 are G protein-coupled receptors that function as carbohydrate sensors in taste buds, gut, and pancreas. Here we report that sweet taste receptors T1R2 and T1R3 are expressed throughout adipogenesis and in adipose tissues. Treatment of mouse and human precursor cells with artificial sweeteners, saccharin and acesulfame potassium, enhanced adipogenesis. Saccharin treatment of 3T3-L1 cells and primary mesenchymal stem cells rapidly stimulated phosphorylation of Akt and downstream targets with functions in adipogenesis such as cAMP-response element-binding protein and FOXO1; however, increased expression of peroxisome proliferator-activated receptor and CCAAT/enhancer-binding protein was not observed until relatively late in differentiation. Saccharin-stimulated Akt phosphorylation at Thr-308 occurred within 5 min, was phosphatidylinositol 3-kinase-dependent, and occurred in the presence of high concentrations of insulin and dexamethasone; phosphorylation of Ser-473 occurred more gradually. Surprisingly, neither saccharin-stimulated adipogenesis nor Thr-308 phosphorylation was dependent on expression of T1R2 and/or T1R3, although Ser-473 phosphorylation was impaired in T1R2/T1R3 double knock-out precursors. In mature adipocytes, artificial sweetener treatment suppressed lipolysis even in the presence of forskolin, and lipolytic responses were correlated with phosphorylation of hormone-sensitive lipase. Suppression of lipolysis by saccharin in adipocytes was also independent of T1R2 and T1R3. These results suggest that some artificial sweeteners have previously uncharacterized metabolic effects on adipocyte differentiation and metabolism and that effects of artificial sweeteners on adipose tissue biology may be largely independent of the classical sweet taste receptors, T1R2 and T1R3.

Original languageEnglish
Pages (from-to)32475-32489
Number of pages15
JournalJournal of Biological Chemistry
Volume288
Issue number45
DOIs
Publication statusPublished - 8 Nov 2013

Keywords

  • Adipogenesis
  • Akt
  • G Protein-coupled Receptors (GPCR)
  • Lipolysis
  • Metabolism
  • Acesulfame K
  • Saccharin
  • T1R2
  • T1R3
  • ADIPOCYTE DIFFERENTIATION
  • BITTER TASTE
  • T1R3 TASTE
  • INSULIN-SECRETION
  • CYCLASE ACTIVITY
  • MAMMALIAN SWEET
  • ADIPOSE-TISSUE
  • BODY-WEIGHT
  • UMAMI TASTE
  • SACCHARIN

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