Improved in vitro model systems for gastrointestinal infection by choice of cell line, pH, microaerobic conditions, and optimization of culture conditions.
BACKGROUND
Commonly used in vitro infection cultures do not mimic the human gastrointestinal tract with regard to pH and microaerobic conditions. Furthermore, despite the importance of mucin-Helicobacter interactions, the cell lines used have not been selected for appropriate mucin expression. To make in vitro studies more applicable to human disease, we have developed coculture methods taking these factors into account.


METHODS
Nine human gastrointestinal epithelial cell lines (MKN1, MKN7, MKN28, MKN45, KATO3, HFE145, PCAA/C11 Caco-2, and LS513) were investigated. Expression and glycosylation of mucins (MUC1, 2, 3, 4, 5AC, 5B, 6, 12, 13, and 16) were determined by immunohistochemistry. We analyzed the effect of microaerobic conditions and acidic pH on cell proliferation, viability, and apoptosis.


RESULTS
Microaerobic culture, which is more physiological for the bacteria, did not adversely affect mammalian cell viability, proliferation, or induce apoptosis The cell lines varied in mucin expression, with MKN7 and MKN45 being most similar to gastric mucosa and Caco-2 and LS513 to intestinal mucosa, although none exactly matched normal mucosa. However, changes in culture conditions did not cause major changes in the mucin expression within cell lines.


CONCLUSIONS
Culture conditions mimicking the natural environment and allowing the bacterial cells to thrive had no effect on cell viability or apoptosis, and very little influence on mucin expression of human gastrointestinal cells. Thus, it is feasible, using the simple methods we present here, to substantially improve bacterial-mammalian cell in vitro coculture studies to make them more reflective of human infection.
Mucosal Diseases Program, Mater Medical Research Institute, Mater Health Services, Aubigny Place, South Brisbane, Queensland 4101, Australia. slinden@mmri.mater.org.au
Sara K
SK
Lindén
Kim M
KM
Driessen
Michael A
MA
McGuckin
D000332:Aerobiosis; D017209:Apoptosis; D018938:Caco-2 Cells; D018929:Cell Culture Techniques / Q000379:methods; D002460:Cell Line; D002470:Cell Survival; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism / Q000382:microbiology*; D005752:Gastric Mucins / Q000378:metabolism; D005753:Gastric Mucosa / Q000166:cytology / Q000378:metabolism / Q000382:microbiology; D005767:Gastrointestinal Diseases / Q000382:microbiology; D016481:Helicobacter Infections / Q000382:microbiology; D016480:Helicobacter pylori / Q000254:growth & development*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007150:Immunohistochemistry
D005752:Gastric Mucins