title: Protective effect of interferon-alpha on the DNA- and RNA-degrading pathway in anti-Fas-antibody induced apoptosis.
abstract: OBJECTIVE
  Fas membrane-associated polypeptide antigen is a receptor molecule responsible for apoptosis-mediated signals. In animal models of acute viral hepatitis, apoptosis of hepatocytes is mediated by Fas-death receptors; therefore, the aim of this study was to evaluate the effect of interferon (IFN)-alpha on apoptotic markers and nuclease activity against different coding and non-coding single and double stranded RNAs during Fas-induced liver apoptosis.
  
  
  METHODS
  An in vivo experiment was performed with simultaneous administration of anti-Fas (CD95) antibodies and IFN-alpha, and an in vitro experiment was performed in hepatocyte cultures treated with anti-Fas antibodies and IFN-alpha.
  
  
  RESULTS
  Detection of apoptosis using Annexin V-FITC/propidium iodide, Bcl-2 and Bax expression in hepatocyte cultures confirmed the appearance of early apoptotic events and progression toward late apoptosis after anti-Fas antibody treatment. IFN-alpha had a tendency to retard the apoptosis process in Fas-induced apoptosis by increasing the number of viable cells and decreasing the number of cells in late apoptosis, by increasing the percentage of Bcl-2 positive cells, by decreasing the percentage of Bax positive cells, and by decreasing the nuclease activity compared to the anti-Fas antibody treated group. Total DNA and RNA concentration was much reduced in the Fas group and DNA fragmentation assay provided evidence for increased DNA degradation. Enhanced nuclease activity against DNA, rRNA, poly(A), poly(C), poly(U), poly(I:C), and poly(A:U) was manifested in the anti-Fas antibody treated group, except for the inhibitory-bound alkaline RNase.
  
  
  CONCLUSIONS
  The results demonstrate that the RNA-degrading pathway in Fas-induced apoptosis can accelerate the liberation of the latent enzyme from the inhibitor complex. IFN-alpha prevented enormous, Fas-ligand induced degradation of all the substrates used in this experimental study, most probably due to similarities in the signal transduction pathways. Investigations of death receptor-induced apoptosis may lead to novel treatment combinations for patients with acute or chronic liver diseases.
authors.affiliation: Institute of Biochemistry and Institute of Physiology, Medical Faculty, University of Nis, Serbia and Montenegro.
authors.forename: Gordana
authors.initials: G
authors.lastname: Kocic
authors.forename: Gordana
authors.initials: G
authors.lastname: Bjelakovic
authors.forename: Dusica
authors.initials: D
authors.lastname: Pavlovic
authors.forename: Tatjana
authors.initials: T
authors.lastname: Jevtovic
authors.forename: Voja
authors.initials: V
authors.lastname: Pavlovic
authors.forename: Dusan
authors.initials: D
authors.lastname: Sokolovic
authors.forename: Jelena
authors.initials: J
authors.lastname: Basic
authors.forename: Snezana
authors.initials: S
authors.lastname: Cekic
authors.forename: Tatjana
authors.initials: T
authors.lastname: Cvetkovic
authors.forename: Radivoj
authors.initials: R
authors.lastname: Kocic
authors.forename: Svetlana
authors.initials: S
authors.lastname: Stojanovic