Rosiglitazone protects against palmitate-induced pancreatic beta-cell death by activation of autophagy via 5'-AMP-activated protein kinase modulation

Endocrine. 2013 Aug;44(1):87-98. doi: 10.1007/s12020-012-9826-5. Epub 2012 Oct 31.

Abstract

Promoting beta-cell survival is crucial for the prevention of beta-cell failure in diabetes. Thiazolidinediones, a widely used drug to improve insulin sensitivity in clinical practice, is found to have a protective effect on islet beta-cell. To date, the mechanism underlying the protective role of thiazolidinedione on beta-cell survival remain largely unknown. Activation of autophagy was detected by transmission electron microscopy, western blot, and GFP-LC3 transfection. Cell viability was examined by WST-8. Cell apoptosis was demonstrated by DAPI and Annexin V/PI staining. Colony formation assay was used to detect long-term cell viability. We demonstrated that rosiglitazone-treated beta-cells were more resistant to palmitate-induced apoptosis. The conversion of LC3-I to LC3-II and accumulated autophagosomes were found to be upregulated in rosiglitazone-treated cells. Inhibition of autophagy augmented palmitate-induced apoptosis with rosiglitazone treatment, suggesting that autophagy plays an important role in the survival function of rosiglitazone on beta-cells. Furthermore, we showed that rosiglitazone could induce AMP-activated protein kinase (AMPK) phosphorylation and reduce p70S6 kinase phosphorylation. Inhibition of AMPK impaired autophagy activation and enhanced palmitate-induced apoptosis during rosiglitazone treatment. These findings reveal that rosiglitazone-induced autophagy contributes to its protective function on beta-cells during palmitate treatment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AMP-Activated Protein Kinases / antagonists & inhibitors
  • AMP-Activated Protein Kinases / genetics
  • AMP-Activated Protein Kinases / metabolism*
  • Animals
  • Autophagy / drug effects*
  • Cell Death / drug effects
  • Cells, Cultured
  • Cytoprotection / drug effects*
  • Drug Evaluation, Preclinical
  • Enzyme Activation / drug effects
  • Hypoglycemic Agents / pharmacology*
  • Insulin-Secreting Cells / drug effects*
  • Insulin-Secreting Cells / physiology
  • Palmitic Acid / adverse effects*
  • RNA, Small Interfering / pharmacology
  • Rats
  • Rosiglitazone
  • Thiazolidinediones / pharmacology*

Substances

  • Hypoglycemic Agents
  • RNA, Small Interfering
  • Thiazolidinediones
  • Rosiglitazone
  • Palmitic Acid
  • AMP-Activated Protein Kinases