Role of GM-CSF in the inflammatory cytokine network that regulates neutrophil influx into the colonic mucosa during Clostridium difficile infection in mice

AJ McDermott, CR Frank, NR Falkowski… - Gut …, 2014 - Taylor & Francis
AJ McDermott, CR Frank, NR Falkowski, RA McDonald, VB Young, GB Huffnagle
Gut microbes, 2014Taylor & Francis
Clostridium difficile infection in antibiotic-treated mice results in acute colitis characterized by
severe intestinal histopathology, robust neutrophil influx, and increased expression of
numerous inflammatory cytokines, including GM-CSF. We utilized a neutralizing monoclonal
antibody (mAb) against GM-CSF in a murine model to study the role of GM-CSF during acute
C. difficile colitis. Cefoperazone-treated mice were challenged with C. difficile (strain 630)
spores. Expression of GM-CSF was significantly increased in animals challenged with C …
Clostridium difficile infection in antibiotic-treated mice results in acute colitis characterized by severe intestinal histopathology, robust neutrophil influx, and increased expression of numerous inflammatory cytokines, including GM-CSF. We utilized a neutralizing monoclonal antibody (mAb) against GM-CSF in a murine model to study the role of GM-CSF during acute C. difficile colitis. Cefoperazone-treated mice were challenged with C. difficile (strain 630) spores. Expression of GM-CSF was significantly increased in animals challenged with C. difficile. Treatment with an anti-GM-CSF mAb did not alter C. difficile colonization levels, weight loss, or expression of IL-22 and RegIIIγ. However, expression of the inflammatory cytokines TNFα and IL-1β, as well as iNOS, was significantly reduced following anti-GM-CSF treatment. Expression of the neutrophil chemokines CXCL1 and CXCL2, but not the chemokines CCL2, CCL4, CXCL9, and CXCL10, was significantly reduced by anti-GM-CSF treatment. Consistent with a decrease in neutrophil-attractant chemokine expression, there were fewer neutrophils in histology sections and a reduction in the expression of secretory leukocyte protease inhibitor (SLPI), a tissue anti-protease that protects against damage by secreted neutrophil elastase. These data indicate that GM-CSF plays a role in the inflammatory signaling network that drives neutrophil recruitment in response to C. difficile infection but does not appear to play a role in clearance of the infection.
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