"Tissue" transglutaminase is specifically expressed in neonatal rat liver cells undergoing apoptosis upon epidermal growth factor-stimulation

M. Piacentini, F. Autuori, L. Dini, M. G. Farrace, L. Ghibelli, L. Piredda, L. Fesus

Research output: Contribution to journalArticle

Abstract

We recently reported that activation of "tissue" transglutaminase (EC 2.3.2.13; tTG) in liver cells undergoing apoptosis determines extensive cross-linking of cellular proteins resulting in the formation of SDS-insoluble shells in the so-called "apoptotic bodies". In attempt to obtain further insight into the role played by tTG in apoptosis of liver cells, we investigated its expression in primary cultures of neonatal rat liver cells stimulated with epidermal growth factor (EGF). EGF-treatment of neonatal rat liver cells induces first hyperplasia of hepatocytes, followed by involution characterized by a high incidence of apoptosis. The proliferative phase of hepatocytes is paralleled by a 10-fold increase in tTG mRNA level, which is followed, during the phase of involution, by sequential increases in enzyme activity and levels of SDS-insoluble apoptotic bodies. tTG immunostaining at both the light- and electron-microscopic levels shows that the most intensive reaction is present in globular structures showing the typical morphological appearance of mature apoptotic bodies. In early apoptotic stages, tTG protein is localized in the perinuclear region of the cell. Intense immunostaining is also found in the apoptotic bodies present inside phagosomes within the cytoplasm of neighboring cells. This evidence confirms and extends our previous findings, indicating that tTG induction and activation specifically takes place in cells undergoing apoptosis, suggesting a key role for the enzyme in the apoptotic program.

Original languageEnglish
Pages (from-to)227-235
Number of pages9
JournalCell & Tissue Research
Volume263
Issue number2
DOIs
Publication statusPublished - Feb 1991

Keywords

  • Apoptosis
  • Cell culture
  • Cell proliferation
  • Epidermal growth factor (EGF)
  • Neonatal hepatocytes

ASJC Scopus subject areas

  • Anatomy
  • Clinical Biochemistry
  • Cell Biology

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