Targeting Cellular Calcium Homeostasis to Prevent Cytokine-Mediated Beta Cell Death

Sci Rep. 2017 Jul 17;7(1):5611. doi: 10.1038/s41598-017-05935-4.

Abstract

Pro-inflammatory cytokines are important mediators of islet inflammation, leading to beta cell death in type 1 diabetes. Although alterations in both endoplasmic reticulum (ER) and cytosolic free calcium levels are known to play a role in cytokine-mediated beta cell death, there are currently no treatments targeting cellular calcium homeostasis to combat type 1 diabetes. Here we show that modulation of cellular calcium homeostasis can mitigate cytokine- and ER stress-mediated beta cell death. The calcium modulating compounds, dantrolene and sitagliptin, both prevent cytokine and ER stress-induced activation of the pro-apoptotic calcium-dependent enzyme, calpain, and partly suppress beta cell death in INS1E cells and human primary islets. These agents are also able to restore cytokine-mediated suppression of functional ER calcium release. In addition, sitagliptin preserves function of the ER calcium pump, sarco-endoplasmic reticulum Ca2+-ATPase (SERCA), and decreases levels of the pro-apoptotic protein thioredoxin-interacting protein (TXNIP). Supporting the role of TXNIP in cytokine-mediated cell death, knock down of TXNIP in INS1-E cells prevents cytokine-mediated beta cell death. Our findings demonstrate that modulation of dynamic cellular calcium homeostasis and TXNIP suppression present viable pharmacologic targets to prevent cytokine-mediated beta cell loss in diabetes.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / metabolism*
  • Cell Death*
  • Cells, Cultured
  • Cytokines / pharmacology*
  • Endoplasmic Reticulum / drug effects
  • Endoplasmic Reticulum / metabolism
  • Endoplasmic Reticulum / pathology
  • Endoplasmic Reticulum Stress / drug effects
  • Homeostasis
  • Inflammation / metabolism
  • Inflammation / pathology
  • Inflammation / prevention & control*
  • Insulin-Secreting Cells / drug effects*
  • Insulin-Secreting Cells / metabolism
  • Insulin-Secreting Cells / pathology
  • Rats
  • Sarcoplasmic Reticulum Calcium-Transporting ATPases / metabolism

Substances

  • Cytokines
  • Sarcoplasmic Reticulum Calcium-Transporting ATPases
  • Calcium