PKCζ phosphorylates TRAF2 to protect against intestinal ischemia-reperfusion-induced injury

Cell Death Dis. 2017 Jul 20;8(7):e2935. doi: 10.1038/cddis.2017.310.

Abstract

Intestinal ischemia-reperfusion (I/R) is a common clinical problem that occurs during various clinical pathological processes. Excessive apoptosis has an indispensable role in intestinal I/R injury. Tumor necrosis factor receptor-associated factor 2 (TRAF2) and PKCζ have an essential role in apoptosis. Here, we aimed to investigate the effects of PKCζ and TRAF2 and to explore the correlation between PKCζ and TRAF2 in intestinal I/R injury. Mice were subjected to intestinal I/R injury in vivo. In vitro experiments were conducted by treating Caco-2 cells with hypoxia/reoxygenation (H/R) stimulation to simulate intestinal I/R. Intestinal tissue samples and Caco-2 cells were examined using various approaches. Intestinal I/R induced the membrane translocation and phosphorylation of PKCζ. Pretreatment with the PKCζ activator phosphatidylcholine remarkably attenuated gut injury by suppressing apoptosis. H/R induced PKCζ to combine with TRAF2, which was phosphorylated by PKCζ at Ser55, but not at Ser11, under intestinal I/R or H/R conditions. In addition, TRAF2 Ser55 phosphorylation increased cell survival by inhibiting cell apoptosis in the H/R model. Mechanistically, TRAF2 Ser55 phosphorylation promoted NF-κB activation but suppressed c-Jun activation in Caco-2 cells under H/R conditions. The results of this study demonstrate that the PKCζ/TRAF2 pathway represents a novel protective mechanism against intestinal I/R injury. Therefore, the PKCζ/TRAF2 pathway is a novel target for potential treatments of intestinal I/R injury-related diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Caco-2 Cells
  • Humans
  • Intestinal Diseases / metabolism*
  • Intestinal Diseases / pathology
  • Intestinal Diseases / prevention & control
  • Male
  • Mice
  • Phosphorylation
  • Protein Kinase C / metabolism*
  • Reperfusion Injury / metabolism*
  • Reperfusion Injury / pathology
  • Reperfusion Injury / prevention & control
  • TNF Receptor-Associated Factor 2 / metabolism*

Substances

  • PSMD2 protein, human
  • TNF Receptor-Associated Factor 2
  • TRAF2 protein, mouse
  • protein kinase C zeta
  • Protein Kinase C