The novel NADPH oxidase 4 selective inhibitor GLX7013114 counteracts human islet cell death in vitro

PLoS One. 2018 Sep 28;13(9):e0204271. doi: 10.1371/journal.pone.0204271. eCollection 2018.

Abstract

It has been proposed that pancreatic beta-cell dysfunction in type 2 diabetes is promoted by oxidative stress caused by NADPH oxidase (Nox) over-activity. The aim of the present study was to evaluate the efficacy of novel Nox inhibitors as protective agents against cytokine- or high glucose + palmitate-induced human beta-cell death. The Nox2 protein was present mainly in the cytoplasm and was induced by cytokines. Nox4 protein immunoreactivity, with some nuclear accumulation, was observed in human islet cells, and was not affected by islet culture in the presence of cytokines or high glucose + palmitate. Nox inhibitors with partial or no isoform selectivity (DPI, dapsone, GLX351322, and GLX481372) all reduced ROS production of human islet cells exposed to high glucose + palmitate. This was paralleled by improved viability and reduced caspase 3 activation. The Nox1 selective inhibitor ML171 failed to reduce human islet cell death in response to both cytokines and high glucose + palmitate. The selective Nox2 inhibitor Phox-I2 also failed to protect against cytokines, but protected partially against high glucose + palmitate-induced cellular death. The highly selective Nox4 inhibitor GLX7013114 protected islet cells against both cytokines and high glucose + palmitate. However, as no osmotic control for high glucose was used, we cannot exclude the possibility that the high glucose effect was due to osmosis. It is concluded that Nox4 may participate in stress-induced islet cell death in human islets in vitro. We propose that Nox4 mediates pro-apoptotic effects in intact islets under stressful conditions and that selective Nox4-inhibition may be a therapeutic strategy in type 2 diabetes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Death / drug effects*
  • Cell Survival / drug effects
  • Dose-Response Relationship, Drug
  • Enzyme Inhibitors / pharmacology*
  • Gene Expression Regulation, Enzymologic / drug effects
  • Glucose / pharmacology
  • HEK293 Cells
  • Humans
  • Islets of Langerhans / cytology*
  • Islets of Langerhans / drug effects*
  • Islets of Langerhans / metabolism
  • Mitochondria / drug effects
  • Mitochondria / metabolism
  • NADPH Oxidase 2 / metabolism
  • NADPH Oxidase 4 / antagonists & inhibitors*
  • NADPH Oxidase 4 / metabolism
  • Palmitic Acid / pharmacology
  • Superoxides / metabolism

Substances

  • Enzyme Inhibitors
  • Superoxides
  • Palmitic Acid
  • NADPH Oxidase 2
  • NADPH Oxidase 4
  • Glucose

Grant support

The present study was supported in part by Olle Engkvist Byggmästare, the Swedish Research Council (2017-01343), the Swedish Diabetes Association, the Novo Nordisk Foundation, the family Ernfors Fund, the Swedish Child Diabetes Fund and EXODIAB. The funder Glucox Biotech AB provided support in the form of salaries for authors EW and PW. Glucox Biotech AB has supported this study by generating, characterizing and providing NOX inhibitors. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.