GQ-16, a novel peroxisome proliferator-activated receptor γ (PPARγ) ligand, promotes insulin sensitization without weight gain

J Biol Chem. 2012 Aug 10;287(33):28169-79. doi: 10.1074/jbc.M111.332106. Epub 2012 May 14.

Abstract

The recent discovery that peroxisome proliferator-activated receptor γ (PPARγ) targeted anti-diabetic drugs function by inhibiting Cdk5-mediated phosphorylation of the receptor has provided a new viewpoint to evaluate and perhaps develop improved insulin-sensitizing agents. Herein we report the development of a novel thiazolidinedione that retains similar anti-diabetic efficacy as rosiglitazone in mice yet does not elicit weight gain or edema, common side effects associated with full PPARγ activation. Further characterization of this compound shows GQ-16 to be an effective inhibitor of Cdk5-mediated phosphorylation of PPARγ. The structure of GQ-16 bound to PPARγ demonstrates that the compound utilizes a binding mode distinct from other reported PPARγ ligands, although it does share some structural features with other partial agonists, such as MRL-24 and PA-082, that have similarly been reported to dissociate insulin sensitization from weight gain. Hydrogen/deuterium exchange studies reveal that GQ-16 strongly stabilizes the β-sheet region of the receptor, presumably explaining the compound's efficacy in inhibiting Cdk5-mediated phosphorylation of Ser-273. Molecular dynamics simulations suggest that the partial agonist activity of GQ-16 results from the compound's weak ability to stabilize helix 12 in its active conformation. Our results suggest that the emerging model, whereby "ideal" PPARγ-based therapeutics stabilize the β-sheet/Ser-273 region and inhibit Cdk5-mediated phosphorylation while minimally invoking adipogenesis and classical agonism, is indeed a valid framework to develop improved PPARγ modulators that retain antidiabetic actions while minimizing untoward effects.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3-L1 Cells
  • Animals
  • Cyclin-Dependent Kinase 5 / genetics
  • Cyclin-Dependent Kinase 5 / metabolism
  • Drug Evaluation, Preclinical
  • Humans
  • Hypoglycemic Agents / chemistry
  • Hypoglycemic Agents / pharmacokinetics
  • Hypoglycemic Agents / pharmacology*
  • Ligands
  • Mice
  • NIH 3T3 Cells
  • PPAR gamma / agonists*
  • PPAR gamma / genetics
  • PPAR gamma / metabolism
  • Phosphorylation / drug effects
  • Phosphorylation / genetics
  • Protein Structure, Secondary
  • Thiazolidinediones / chemistry
  • Thiazolidinediones / pharmacokinetics
  • Thiazolidinediones / pharmacology*
  • U937 Cells
  • Weight Gain*

Substances

  • 5-(5-bromo-2-methoxybenzylidene)-3-(4-methyl-benzyl)thiazolidine-2,4-dione
  • Hypoglycemic Agents
  • Ligands
  • PPAR gamma
  • Thiazolidinediones
  • Cyclin-Dependent Kinase 5
  • CDK5 protein, human
  • Cdk5 protein, mouse

Associated data

  • PDB/3T03