Activation of the NLRP3 inflammasome complex is not required for stress-induced death of pancreatic islets

PLoS One. 2014 Nov 18;9(11):e113128. doi: 10.1371/journal.pone.0113128. eCollection 2014.

Abstract

Loss of pancreatic beta cells is a feature of type-2 diabetes. High glucose concentrations induce endoplasmic reticulum (ER) and oxidative stress-mediated apoptosis of islet cells in vitro. ER stress, oxidative stress and high glucose concentrations may also activate the NLRP3 inflammasome leading to interleukin (IL)-1β production and caspase-1 dependent pyroptosis. However, whether IL-1β or intrinsic NLRP3 inflammasome activation contributes to beta cell death is controversial. This possibility was examined in mouse islets. Exposure of islets lacking functional NLRP3 or caspase-1 to H2O2, rotenone or thapsigargin induced similar cell death as in wild-type islets. This suggests that oxidative or ER stress do not cause inflammasome-mediated cell death. Similarly, deficiency of NLRP3 inflammasome components did not provide any protection from glucose, ribose or gluco-lipotoxicity. Finally, genetic activation of NLRP3 specifically in beta cells did not increase IL-1β production or cell death, even in response to glucolipotoxicity. Overall, our results show that glucose-, ER stress- or oxidative stress-induced cell death in islet cells is not dependent on intrinsic activation of the NLRP3 inflammasome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Animals
  • Apoptosis / physiology*
  • Blotting, Western
  • Carrier Proteins / metabolism*
  • DNA Primers / genetics
  • Diabetes Mellitus, Type 2 / metabolism*
  • Endoplasmic Reticulum Stress / physiology*
  • Enzyme-Linked Immunosorbent Assay
  • Genotype
  • Islets of Langerhans / metabolism
  • Islets of Langerhans / physiopathology*
  • Mice
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Polymerase Chain Reaction

Substances

  • Carrier Proteins
  • DNA Primers
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Nlrp3 protein, mouse

Grants and funding

This study was supported by a National Health and Medical Research Council of Australia (NHMRC; http://www.nhmrc.gov.au/) and Juvenile Diabetes Research Foundation (JDRF; http://www.jdrf.org/) joint special program grant in type 1 diabetes (APP466658), an NHMRC project grant (APP1032610), fellowships from the NHMRC (HET and SLM) and a University of Melbourne Viola Edith Reid Bequest Scholarship (JAW). This study was supported in part by the Victorian Government’s Operational Infrastructure Support Program (http://www.business.vic.gov.au/grants-and-assistance/programs/medical-research-operational-infrastructure-program). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.