A novel paraptosis pathway involving LEI/L-DNaseII for EGF-induced cell death in somato-lactotrope pituitary cells

Apoptosis. 2006 Mar;11(3):367-75. doi: 10.1007/s10495-006-4568-6.

Abstract

We have recently reported that EGF triggers an original form of cell death in pituitary cell line (GH4C1) with a phenotype sharing some characteristics of both apoptosis (internucleosomal DNA fragmentation) and paraptosis (caspase-independence and cytoplasmic vacuolization). However, the endonuclease involved in EGF-induced DNA fragmentation has not been assessed so far. In the present work we therefore further explored the putative paraptosis involvement in EGF-induced cell death and asked whether L-DNaseII might be involved. Indeed, this endonuclease is known to mediate internucleosomal DNA fragmentation in caspase independent manner. Our Western blot, immunocytochemistry and enzymatic measurement assays show that EGF triggers a cleavage of Leukocyte Elastase Inhibitor (LEI) precursor into L-DNaseII, its subsequent enzymatic activation and nuclear translocation thus pointing to the involvement of this endonuclease pathway in caspase-independent DNA fragmentation. In addition, EGF-induced cell death can be blocked by paraptosis inhibitor AIP-1/Alix, but not with its anti-apoptotic C-terminal fragment (Alix-CT). Altogether these data suggest that EGF-induced cell death defines a novel, L-DNaseII-mediated form of paraptosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects*
  • Apoptosis / physiology
  • Calcium-Binding Proteins / genetics
  • Calcium-Binding Proteins / metabolism
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Cells, Cultured
  • DNA Fragmentation
  • Endodeoxyribonucleases / metabolism*
  • Epidermal Growth Factor / metabolism
  • Epidermal Growth Factor / pharmacology*
  • Lactotrophs / cytology
  • Lactotrophs / drug effects*
  • Lactotrophs / physiology
  • Leukocyte Elastase / antagonists & inhibitors*
  • Pituitary Gland / cytology
  • Protein Precursors / metabolism
  • Rats
  • Signal Transduction / drug effects*
  • Signal Transduction / physiology
  • Somatotrophs / cytology
  • Somatotrophs / drug effects*
  • Somatotrophs / physiology

Substances

  • Calcium-Binding Proteins
  • Carrier Proteins
  • Pdcd6ip protein, rat
  • Protein Precursors
  • Epidermal Growth Factor
  • Endodeoxyribonucleases
  • deoxyribonuclease II
  • Leukocyte Elastase