Diabetologia

, Volume 37, Issue 8, pp 733–738

DNA fragmentation is an early event in cytokine-induced islet beta-cell destruction

  • A. Rabinovitch
  • W. L. Suarez-Pinzon
  • Y. Shi
  • A. R. Morgan
  • R. C. Bleackley
Originals

DOI: 10.1007/BF00404328

Cite this article as:
Rabinovitch, A., Suarez-Pinzon, W.L., Shi, Y. et al. Diabetologia (1994) 37: 733. doi:10.1007/BF00404328

Summary

The cytokines, interleukin 1, tumour necrosis factor, and interferon gamma are cytotoxic to islet beta cells, however, their mechanisms of beta-cell killing are not fully characterized. Since DNA damage is a mechanism of cytokine-induced cell death in some cell types, we sought evidence for cytotoxic effects of cytokines at a nuclear level in islet beta cells by measuring DNA fragmentation in rat islets and islet beta-cell lines. The individual cytokines, interleukin 1 (10 U/ml), tumour recrosis factor (103 U/ml) and interferon gamma (103 U/ml) inhibited insulin release from rat islets, but did not cause DNA fragmentation or destroy islet cells; by contrast, combination of the three cytokines induced DNA fragmentation and islet-cell death. Cytokine-induced DNA fragmentation preceded cell lysis in islet beta-cell lines (RINm5F, rat insulinoma cells; and NIT-1, NOD/Lt mouse transgenic beta cells), whereas in non-islet cell lines (GH-3, rat pituitary; and PC-12, rat adrenal) the cytokines induced cell lysis and no or late DNA fragmentation. Nicotinamide prevented both DNA fragmentation and destruction of RINm5F islet cells by the cytokines. These findings identify DNA as an early target of cytokine action in islet beta cells, and implicate DNA fragmentation as a mechanism of cytokine-induced beta-cell destruction.

Key words

Islet beta cells cytokines interleukin 1 tumour necrosis factor interferon gamma DNA damage 

Abbreviations

IDDM

Insulin-dependent diabetes mellitus

IL-1

interleukin-1

TNF

tumour necrosis factor

IFNγ

interferon gamma

NO

nitric oxide

l-NMMA

l-NG-monomethyl arginine

Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  • A. Rabinovitch
    • 1
  • W. L. Suarez-Pinzon
    • 1
  • Y. Shi
    • 2
  • A. R. Morgan
    • 3
  • R. C. Bleackley
    • 3
  1. 1.Department of Medicine and the Muttart Diabetes Research and Training CentreUniversity of AlbertaEdmontonCanada
  2. 2.Department of ImmunologyUniversity of AlbertaEdmontonCanada
  3. 3.Department of Biochemistry, CentreUniversity of AlbertaEdmontonCanada
  4. 4.430 Heritage Medical Research CentreUniversity of AlbertaEdmontonCanada