title: In vitro cytopathic effects of a cysteine protease of Tritrichomonas foetus on cultured bovine uterine epithelial cells.
abstract: OBJECTIVE
  To evaluate the cytopathic effects of Tritrichomonas foetus and a purified cysteine protease (ie, CP30) of T foetus on cultured bovine uterine epithelial cells (BUECs) in vitro.
  
  
  METHODS
  10 reproductive tracts were obtained from late-term bovine fetuses at a commercial abattoir.
  
  
  METHODS
  An in vitro culture system of BUECs was developed to study the cytopathic effects of T foetus and purified CP30 of T foetus on host cells. Cytotoxicity of T foetus or CP30 on exposed BUECs was determined. Fluorescence microscopy and flow cytometry analyses were used to detect apoptosis. A fluorometric assay was used to detect BUEC caspase 3 activation. The CP inhibitor E-64 and a caspase inhibitor were used to inhibit apoptosis.
  
  
  RESULTS
  Cytopathic effects were observed in BUECs treated with parasites or CP30 and were concentration and time dependent. The BUECs underwent apoptosis in the presence of parasites or CP30. The specific CP inhibitor E-64 abolished the induction of apoptosis in BUECs by CP30. The caspase inhibitor reduced the amount of apoptosis in BUECs.
  
  
  CONCLUSIONS
  T foetus and its CP30 induce apoptosis in cultured BUECs in vitro. Induction of apoptosis by CP30 is correlated with protease activity. Endometrial cell death as a result of a T foetus infection is likely to be more important in mediating infertility than a direct effect on the conceptus. Provoking an apoptotic reaction in the host may mitigate an inflammatory reaction or immune response and therefore favor survival of the parasite in a chronic infection.
authors.affiliation: Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
authors.forename: Bibhuti N
authors.initials: BN
authors.lastname: Singh
authors.forename: Gary R
authors.initials: GR
authors.lastname: Hayes
authors.forename: John J
authors.initials: JJ
authors.lastname: Lucas
authors.forename: David H
authors.initials: DH
authors.lastname: Beach
authors.forename: Robert O
authors.initials: RO
authors.lastname: Gilbert
mesh_terms: D000818:Animals; D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002417:Cattle / Q000469:parasitology*; D002478:Cells, Cultured; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D053938:DNA Fragmentation / Q000502:physiology; D004789:Enzyme Activation; D004847:Epithelial Cells / Q000469:parasitology* / Q000473:pathology*; D005260:Female; D008856:Microscopy, Fluorescence; D016835:Tritrichomonas foetus / Q000201:enzymology*; D014599:Uterus / Q000166:cytology / Q000469:parasitology*
chemical_list: D053148:Caspase 3; D020169:Caspases; D003546:Cysteine Endopeptidases