title: Comparative Effect of Recombinant Shiga Toxin in Induction of Pro- and Anti-Apoptotic Markers and Inflammatory Cytokines in Epithelial and Monocytic Cells.
abstract: BACKGROUND
  Shiga toxins (Stxs, also referred to as verotoxins) are a family of bacterial protein toxins generated by Stx producing-Escherichia coli (STEC), such as E. coli serotype O157:H7.
  
  
  OBJECTIVE
  The aim of this study was to investigate the effect of recombinant and native Shiga toxin (Stx) in induction of pro- and anti-apoptosis factors and stimulation of immune response to HeLa and THP-1 cells.
  
  
  METHODS
  The HeLa and THP-1 cells were used to study the effect of native and recombinant Shiga toxin. For this purpose, 10(6) cells were cultured overnight in six-well plates and different concentrations of Stx were added to each well. The cells were then collected after 24 hours of incubation. Total RNA and protein was extracted. Firstly, the total RNA was used in reverse transcription-polymerase chain reaction (RT-PCR) for detection of interleukin (IL)-1α, IL-1β, IL-8, tumor necrosis factor (TNF)-α, B-cell lymphoma (Bcl)-2 and Bcl-xl transcript. Protein expression of pro- and anti-apoptotic factors was also confirmed by western blot analysis.
  
  
  RESULTS
  The IL-1α and IL-8 were increased by recombinant and native Stx. Interleukin-1β was detected in THP-1, while TNF-α was detected HeLa cells. Furthermore, Bcl-2 and Bcl-xl expression was observed in HeLa cells. However, expression of Bak was reduced by recombinant Stx and native toxin at the protein level, while Bcl-xl expression was increased.
  
  
  CONCLUSIONS
  These results suggest that toxins induce inflammatory responses, particularly through expression of chemokine. Recombinant Stx and native toxin induced apoptosis by balancing between different pro- and anti-apoptotic Bcl-2 family-factors in epithelial cells. In this study, for the first time, recombinant and native Stx induction of apoptotic factors and stimulation of immune response to HeLa and THP-1 cells were compared.
authors.affiliation: Molecular Biology Department, Pasteur Institute of Iran, Tehran, IR Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Abedi Jafari
authors.affiliation: Molecular Biology Department, Pasteur Institute of Iran, Tehran, IR Iran.
authors.forename: Mana
authors.initials: M
authors.lastname: Oloomi
authors.affiliation: Molecular Biology Department, Pasteur Institute of Iran, Tehran, IR Iran.
authors.forename: Saeid
authors.initials: S
authors.lastname: Bouzari
keywords: Apoptosis; Cytokines; HeLa Cells; Shiga Toxin; THP-1