Bacteria and bacterial rRNA genes associated with the development of colitis in IL-10(-/-) mice.
BACKGROUND
Microorganisms appear to play important yet ill-defined roles in the etiology of inflammatory bowel disease (IBD). This study utilized a novel population-based approach to identify bacteria and bacterial rRNA genes associated with the development of colitis in IL-10(-/-) mice.


METHODS
Mice were housed in 2 environments: a community mouse facility where the mice were fed nonsterile chow (Room 3) and a limited access facility where the mice were fed sterile chow (Room 4). Every month the disease activity levels were assessed and fecal bacterial compositions were analyzed. At the end of the experiments histological and bacterial analyses were performed on intestinal tissue.


RESULTS
Although disease activity increased over time in both environments, it progressed at a faster rate in Room 3 than Room 4. Culture and culture-independent bacterial analyses identified several isolates and phylotypes associated with colitis. Two phylotypes (GpC2 and Gp66) were distinguished by their negative associations with disease activity in fecal and tissue samples. Notably, rRNA genes from these phylotypes had high sequence identity (99%) to an rRNA gene from a previously described flagellated Clostridium (Lachnospiraceae bacterium A4).


CONCLUSIONS
The negative associations of these 2 phylotypes (GpC2 and Gp66) suggest that these bacteria were being immunologically targeted, consistent with prior findings that the Lachnospiraceae bacterium A4 bears a prevalent flagellar antigen for disease-associated immunity in murine immune colitis and human Crohn's disease. Identification of these associations suggests that the experimental approach used in this study will have considerable utility in elucidating the host-microbe interactions underlying IBD.
Ye
Jingxiao
J
Department of Plant Pathology and Microbiology, University of California, Riverside, California.
Lee
Jimmy W
JW
Division of Biomedical Sciences, University of California, Riverside, California.
Presley
Laura L
LL
Department of Plant Pathology and Microbiology, University of California, Riverside, California.
Bent
Elizabeth
E
Department of Plant Pathology and Microbiology, University of California, Riverside, California.
Wei
Bo
B
Department of Pathology and Laboratory Medicine, University of California, Los Angeles, California.
Braun
Jonathan
J
Department of Pathology and Laboratory Medicine, University of California, Los Angeles, California.
Schiller
Neal L
NL
Division of Biomedical Sciences, University of California, Riverside, California.
Straus
Daniel S
DS
Division of Biomedical Sciences, University of California, Riverside, California.
Borneman
James
J
Department of Plant Pathology and Microbiology, University of California, Riverside, California.
D000818:Animals; D001483:Base Sequence; D003092:Colitis / Q000382:microbiology* / Q000473:pathology*; D005407:Flagella / Q000276:immunology*; D020869:Gene Expression Profiling; D020459:Genes, rRNA / Q000235:genetics*; D016753:Interleukin-10; D051379:Mice; D008809:Mice, Inbred C3H; D010641:Phenotype; D016133:Polymerase Chain Reaction
D016753:Interleukin-10