Hyperthermia with mild electrical stimulation protects pancreatic β-cells from cell stresses and apoptosis

Diabetes. 2012 Apr;61(4):838-47. doi: 10.2337/db11-1098. Epub 2012 Feb 23.

Abstract

Induction of heat shock protein (HSP) 72 improves metabolic profiles in diabetic model mice. However, its effect on pancreatic β-cells is not known. The current study investigated whether HSP72 induction can reduce β-cell stress signaling and apoptosis and preserve β-cell mass. MIN6 cells and db/db mice were sham-treated or treated with heat shock (HS) and mild electrical stimulation (MES) (HS+MES) to induce HSP72. Several cellular markers, metabolic parameters, and β-cell mass were evaluated. HS+MES treatment or HSP72 overexpression increased HSP72 protein levels and decreased tumor necrosis factor (TNF)-α-induced Jun NH(2)-terminal kinase (JNK) phosphorylation, endoplasmic reticulum (ER) stress, and proapoptotic signal in MIN6 cells. In db/db mice, HS+MES treatment for 12 weeks significantly improved insulin sensitivity and glucose homeostasis. Upon glucose challenge, a significant increase in insulin secretion was observed in vivo. Compared with sham treatment, levels of HSP72, insulin, pancreatic duodenal homeobox-1, GLUT2, and insulin receptor substrate-2 were upregulated in the pancreatic islets of HS+MES-treated mice, whereas JNK phosphorylation, nuclear translocation of forkhead box class O-1, and nuclear factor-κB p65 were reduced. Apoptotic signals, ER stress, and oxidative stress markers were attenuated. Thus, HSP72 induction by HS+MES treatment protects β-cells from apoptosis by attenuating JNK activation and cell stresses. HS+MES combination therapy may preserve pancreatic β-cell volume to ameliorate glucose homeostasis in diabetes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus
  • Animals
  • Apoptosis / physiology*
  • Body Weight
  • Eating
  • Electric Stimulation
  • Endoplasmic Reticulum / physiology
  • Forkhead Box Protein O1
  • Forkhead Transcription Factors / genetics
  • Forkhead Transcription Factors / metabolism
  • Gene Expression Regulation / physiology
  • Glucose / metabolism
  • HSP72 Heat-Shock Proteins / genetics
  • HSP72 Heat-Shock Proteins / metabolism
  • Homeostasis
  • Hot Temperature*
  • Insulin / metabolism
  • Insulin-Secreting Cells / physiology*
  • MAP Kinase Kinase 4 / genetics
  • MAP Kinase Kinase 4 / metabolism
  • Male
  • Mice
  • Mice, Inbred NOD
  • Phosphorylation
  • Stress, Physiological / physiology*
  • Tumor Necrosis Factor-alpha / pharmacology

Substances

  • Forkhead Box Protein O1
  • Forkhead Transcription Factors
  • Foxo1 protein, mouse
  • HSP72 Heat-Shock Proteins
  • Insulin
  • Tumor Necrosis Factor-alpha
  • MAP Kinase Kinase 4
  • Glucose