Recipient Organization
TUFTS UNIVERSITY
200 WESTBORO ROAD
N. GRAFTON,MA 01536
Performing Department
Infectious Disease and Global Health
Non Technical Summary
Clostridium difficile, an etiologic agent for pseudomembranous colitis, accounts for a quarter cases of antibiotic-associated diarrhea. The incidence of C. difficile infection (CDI) has increased significantly in both North America and Europe, causing lengthy hospitalization, substantial morbidity and mortality. Our long-term goal is to understand the mechanisms mediating intestinal inflammation in C. difficile infection and to utilize this knowledge for the design of better immune interventions in order to reduce the incidence of CDI and severity of the disease.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Goals / Objectives
With the recent emergence of hypervirulent strains, the incidence of C. difficile infection (CDI) has increased significantly in both North America and Europe, causing lengthy hospitalization, substantial morbidity and mortality. CDI is thought to be mainly mediated by exotoxins TcdA and TcdB, which glucosylate low molecular mass GTPase of the Rho family, leading to massive fluid secretion, acute inflammation, and necrosis of the colonic mucosa. Our long-term goal is to understand the mechanisms mediating intestinal inflammation in C. difficile infection and to utilize this knowledge for the design of better immune interventions in order to reduce the incidence of CDI and severity of the disease. The interaction of intestinal epithelial cells (IECs) with intestinal antigen presenting cells (APCs) in the gut, such as dendritic cells (DCs) and macrophages, orchestrates mucosal immune homeostasis and inflammatory response. Our objective is to elucidate the immune response of IECs and intestinal DCs after their exposure to C. difficile toxins and to determine the nature of their interaction on initiating intestinal inflammation and tissue destruction. We expect to gain a better understanding of not only the underlying mechanisms by which C. difficile toxins induce severe enterocolitis, but also the role of IEC-DC interaction in the onset and development of intestinal inflammatory diseases in general. We believe that such an understanding will help us to design better immune interventions against CDI and other intestinal inflammatory diseases.
Project Methods
To achieve our objective, we will test several working hypotheses: 1) C. difficile toxin-intoxicated IECs are capable of mobilizing and activating DCs; 2) In severe cases of CDI, C. difficile toxins can cross a severely damaged intestinal barrier and further activate DCs and macrophages; and 3) proinflammatory cytokine TNF-alpha synergizes with the toxins to induce apoptosis of IECs, thus exacerbating tissue destruction and enterocolitis.