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An Adipocyte Cell Culture Model to Study the Impact of Protein and Micro-RNA Modulation on Adipocyte Function
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Regulation of adipocyte differentiation and insulin action with rapamycin

Hye Jin Cho1, Jiyoung Park, Hyun Woo Lee

  • 1School of Biological Sciences, Seoul National University, Seoul 151-742, Republic of Korea.

Biochemical and Biophysical Research Communications
|September 11, 2004
PubMed

Insights

Rapamycin inhibits adipocyte differentiation and insulin signaling by impacting adipogenesis and lipogenesis. This mTOR inhibitor affects key gene expression and glucose uptake, highlighting mTOR

Area of Science:

  • Cell Biology
  • Metabolism
  • Molecular Endocrinology

Background:

  • Mammalian target of rapamycin (mTOR) is a key regulator of cell growth and metabolism.
  • Adipocyte differentiation (adipogenesis) and insulin signaling are crucial for metabolic homeostasis.
  • The precise role of mTOR in adipogenesis and insulin action requires further elucidation.

Purpose of the Study:

  • To investigate the effects of mTOR inhibition using rapamycin on adipocyte differentiation and insulin signaling.
  • To determine the impact of rapamycin on adipogenesis, lipogenesis, and insulin-dependent glucose uptake.
  • To elucidate the role of mTOR in the execution of adipogenic programming and insulin action.

Main Methods:

  • Utilized 3T3-L1 and 3T3-F442A cell lines for adipogenesis studies.
  • Administered rapamycin to inhibit mTOR signaling.
  • Assessed adipocyte marker gene expression (PPARγ, adipsin, aP2, ADD1/SREBP1c, FAS).
  • Quantified intracellular lipid accumulation.
  • Evaluated insulin-stimulated phosphorylation of AKT and GSK.
  • Measured insulin-dependent glucose uptake.

Main Results:

  • Rapamycin significantly reduced adipocyte marker gene expression and intracellular lipid accumulation in both cell lines.
  • The inhibitory effect of rapamycin on adipogenesis persisted throughout differentiation, not limited to clonal expansion.
  • Chronic rapamycin treatment blunted insulin-stimulated AKT and GSK phosphorylation and reduced glucose uptake in differentiated adipocytes.
  • Constitutive mTOR activation appears necessary for adipogenic programming.

Conclusions:

  • mTOR inhibition by rapamycin impairs adipocyte differentiation by suppressing adipogenesis and lipogenesis.
  • Rapamycin downregulates insulin signaling and glucose uptake in mature adipocytes.
  • mTOR plays a critical role in both adipogenesis and the regulation of insulin action.

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