title: Cell cycle arrest and apoptosis induced by enteroaggregative Escherichia coli in cultured human intestinal epithelial cells.
abstract: OBJECTIVE
  Enteroaggregative Escherichia coli (EAEC) is an emerging enteric pathogen causing diarrhoeal diseases in multiple epidemiological and clinical settings. However, understanding of the pathogenesis of the disease caused by this organism is still suboptimal. Studies have indicated that enteric bacteria induced cell cycle arrest and apoptosis in host intestinal epithelial cells might play a vital role in the pathogenesis caused by these organisms. In this study an attempt was made to assess EAEC-induced apoptosis and cell cycle modulation in human intestinal epithelial cell lines.
  
  
  METHODS
  INT-407 and HCT-15 cells were infected with EAEC-T8 (clinical isolate) as well as plasmid cured variant of EAEC-T8 (EAEC-pT8). Propidium iodide staining was done to select the time of infection and the incubation period of the infected culture. Apoptosis was further assessed in EAEC infected both the cell lines by annexin-V-FLUOS & propidium iodide, cell death detection ELISA, DNA strand breaks and microscopic analysis. Further, the DNA content of the EAEC-infected cells at different phases of cell cycle was also monitored.
  
  
  RESULTS
  We have found that EAEC could induce apoptosis in human small intestinal as well as colonic epithelial cell lines, which was assessed by the expression of phosphatidylserine on host cell surface, internucleosomal cleavage of host cell DNA and microscopic analysis of the characteristic apoptotic features of these cells. EAEC was also found to arrest cells at S phase and G2-M phase of the cell cycle.
  
  
  CONCLUSIONS
  EAEC-T8 could induce maximum apoptosis and cell cycle modulation in both small intestinal and colonic epithelial cells. Further, we have observed that the plasmid of this organism had maximum contribution to these processes. The outcome of this study has undoubtedly led to a better understanding of the basic mechanism of pathogenesis caused by EAEC.
authors.affiliation: Department of Experimental Medicine and Biotechnology, Post Graduate Institute of Medical Education & Research, Chandigarh 160012, India.
authors.forename: Anshu
authors.initials: A
authors.lastname: Priya
authors.affiliation: Department of Experimental Medicine and Biotechnology, Post Graduate Institute of Medical Education & Research, Chandigarh 160012, India.
authors.forename: Kiranjeet
authors.initials: K
authors.lastname: Kaur
authors.affiliation: Department of Biophysics, Post Graduate Institute of Medical Education & Research, Chandigarh 160012, India.
authors.forename: Shalmoli
authors.initials: S
authors.lastname: Bhattacharyya
authors.affiliation: Department of Experimental Medicine and Biotechnology, Post Graduate Institute of Medical Education & Research, Chandigarh 160012, India.
authors.forename: Anuradha
authors.initials: A
authors.lastname: Chakraborti
authors.affiliation: Department of Experimental Medicine and Biotechnology, Post Graduate Institute of Medical Education & Research, Chandigarh 160012, India.
authors.forename: Sujata
authors.initials: S
authors.lastname: Ghosh
mesh_terms: D017209:Apoptosis; D001422:Bacterial Adhesion; D059447:Cell Cycle Checkpoints; D045744:Cell Line, Tumor; D004847:Epithelial Cells / Q000166:cytology / Q000382:microbiology*; D004926:Escherichia coli / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology; D006801:Humans; D007422:Intestines / Q000166:cytology; D010718:Phosphatidylserines / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism
chemical_list: D010718:Phosphatidylserines