Salmonella induces prominent gene expression in the rat colon.
BACKGROUND
Salmonella enteritidis is suggested to translocate in the small intestine. In vivo it induces gene expression changes in the ileal mucosa and Peyer's patches. Stimulation of Salmonella translocation by dietary prebiotics fermented in colon suggests involvement of the colon as well. However, effects of Salmonella on colonic gene expression in vivo are largely unknown. We aimed to characterize time dependent Salmonella-induced changes of colonic mucosal gene expression in rats using whole genome microarrays. For this, rats were orally infected with Salmonella enteritidis to mimic a foodborne infection and colonic gene expression was determined at days 1, 3 and 6 post-infection (n = 8 rats per time-point). As fructo-oligosaccharides (FOS) affect colonic physiology, we analyzed colonic mucosal gene expression of FOS-fed versus cellulose-fed rats infected with Salmonella in a separate experiment. Colonic mucosal samples were isolated at day 2 post-infection.


RESULTS
Salmonella affected transport (e.g. Chloride channel calcium activated 6, H+/K+ transporting Atp-ase), antimicrobial defense (e.g. Lipopolysaccharide binding protein, Defensin 5 and phospholipase A2), inflammation (e.g. calprotectin), oxidative stress related genes (e.g. Dual oxidase 2 and Glutathione peroxidase 2) and Proteolysis (e.g. Ubiquitin D and Proteosome subunit beta type 9). Furthermore, Salmonella translocation increased serum IFN gamma and many interferon-related genes in colonic mucosa. The gene most strongly induced by Salmonella infection was Pancreatitis Associated Protein (Pap), showing >100-fold induction at day 6 after oral infection. Results were confirmed by Q-PCR in individual rats. Stimulation of Salmonella translocation by dietary FOS was accompanied by enhancement of the Salmonella-induced mucosal processes, not by induction of other processes.


CONCLUSIONS
We conclude that the colon is a target tissue for Salmonella, considering the abundant changes in mucosal gene expression.
Rodenburg
Wendy
W
TI Food and Nutrition, PO Box 557, 6700 AN, Wageningen, The Netherlands. wendy.rodenburg@wur.nl
Keijer
Jaap
J
Kramer
Evelien
E
Roosing
Susanne
S
Vink
Carolien
C
Katan
Martijn B
MB
van der Meer
Roelof
R
Bovee-Oudenhoven
Ingeborg M J
IM
D000284:Administration, Oral; D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D007421:Intestine, Small / Q000378:metabolism* / Q000382:microbiology; D037181:Lectins, C-Type / Q000235:genetics / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D000073718:Pancreatitis-Associated Proteins; D051381:Rats; D012481:Salmonella Infections, Animal / Q000382:microbiology; D012477:Salmonella enteritidis / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000502:physiology*
D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D037181:Lectins, C-Type; D000073718:Pancreatitis-Associated Proteins; C000612141:REG3A protein, human; C000612144:Reg3b protein, rat