Autoimmunity Links Vinculin to the Pathophysiology of Chronic Functional Bowel Changes Following Campylobacter jejuni Infection in a Rat Model
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Acute gastroenteritis can precipitate irritable bowel syndrome (IBS) in humans. Cytolethal distending toxin is common to all pathogens causing gastroenteritis. Its active subunit, CdtB, is associated with post-infectious bowel changes in a rat model of Campylobacter jejuni infection, including small intestinal bacterial overgrowth (SIBO).
To evaluate the role of host antibodies to CdtB in contributing to post-infectious functional sequelae in this rat model.
Ileal tissues from non-IBS human subjects, C. jejuni-infected and control rats were immunostained with antibodies to CdtB, c-Kit, S-100, PGP 9.5 and vinculin. Cytosolic and membrane proteins from mouse enteric neuronal cell lysates were immunoprecipitated with anti-CdtB and analyzed by mass spectrometry. ELISAs were performed on rat cardiac serum using CdtB or vinculin as antigens.
Anti-CdtB antibodies bound to a cytosolic protein in interstitial cells of Cajal (ICC) and myenteric ganglia in C. jejuni-infected and naïve rats and human subjects. Mass spectrometry identified vinculin, confirmed by co-localization and ELISAs. Anti-CdtB antibodies were higher in C. jejuni-infected rats (1.27 ± 0.15) than controls (1.76 ± 0.12) (P < 0.05), and rats that developed SIBO (2.01 ± 0.18) vs. rats that did not (1.44 ± 0.11) (P = 0.019). Vinculin expression levels were reduced in C. jejuni-infected rats (0.058 ± 0.053) versus controls (0.087 ± 0.023) (P = 0.0001), with greater reductions in rats with two C. jejuni infections (P = 0.0001) and rats that developed SIBO (P = 0.001).
Host anti-CdtB antibodies cross-react with vinculin in ICC and myenteric ganglia, required for normal gut motility. Circulating antibody levels and loss of vinculin expression correlate with number of C. jejuni exposures and SIBO, suggesting that effects on vinculin are important in the effects of C. jejuni infection on the host gut.
KeywordsIrritable bowel syndrome Cytolethal distending toxin Vinculin Small intestinal bacterial overgrowth
The antibody to the near-full-length CdtB protein used in this study was provided by Dr. Patricia Guerry (Naval Medical Research Center, Silver Spring, MD), and the recombinant CdtB protein used in this study was provided by Dr. Kenneth Bradley, MIMG Department, UCLA. This work was supported by grants from the Beatrice and Samuel A. Seaver Foundation (MP), the Shoolman Foundation (MP) and the Hansch Family Fund (MP), and by RO1 DK080684 (SS) and a VA-MERIT award (SS).
Conflict of interest
Mark Pimentel has received grants from and is a consultant for Salix Pharmaceuticals and Commonwealth Laboratories, with whom Cedars-Sinai has licensing agreements. The remaining authors have no conflicts to disclose.
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