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Regulation of adiponectin receptor 2 expression via PPAR-alpha in NIT-1 cells

Tae Woo Jung1, Myung Won Lee, Yong Jik Lee

  • 1Samsung Biomedical Institute, Seoul, Korea.

Endocrine Journal
|April 2, 2009
PubMed

Insights

Adiponectin receptor 2 (AdiR2) expression in beta cells changes with lipid levels, potentially impacting diabetes. Peroxisome proliferator-activated receptor-alpha (PPAR-alpha) influences this regulation.

Area of Science:

  • Endocrinology
  • Metabolic Research
  • Diabetes Pathophysiology

Background:

  • Adiponectin receptors are key to adiponectin's antidiabetic actions.
  • Their expression in pancreatic beta cells, crucial for diabetes, remains largely uncharacterized.
  • Adiponectin receptor 2 (AdiR2) is investigated due to its potential role in beta cell function.

Purpose of the Study:

  • To investigate the expression of adiponectin receptor 2 (AdiR2) in beta cells.
  • To determine how hyperlipidemic conditions affect AdiR2 expression in beta cells.
  • To elucidate the regulatory mechanisms, including the role of peroxisome proliferator-activated receptor-alpha (PPAR-alpha), in AdiR2 expression.

Main Methods:

  • Quantitative analysis of AdiR2 expression in beta cells under varying lipid conditions.
  • Treatment with clofibrate (PPAR-alpha agonist) and palmitate.
  • Use of small interfering RNA (siRNA) targeting PPAR-alpha to assess regulatory pathways.

Main Results:

  • AdiR2 expression was elevated under acute hyperlipidemic conditions but reduced under chronic conditions.
  • Impaired AdiR2 expression correlated with diminished beta cell function.
  • Clofibrate treatment delayed palmitate-induced impairment of AdiR2 and PPAR-alpha expression.
  • PPAR-alpha targeted siRNA abolished the protective effect of clofibrate.

Conclusions:

  • Beta cell AdiR2 expression is dynamically regulated by lipid exposure.
  • Chronic hyperlipidemia impairs AdiR2 expression, potentially contributing to beta cell dysfunction in diabetes.
  • The findings suggest a regulatory role for peroxisome proliferator-activated receptor-alpha (PPAR-alpha) in mediating the effects of palmitate on AdiR2 expression in beta cells.

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