Defining host and clostridioides difficile responses to metal and oxidative stress during inflammation
Active Project Grant Awarded Last action
- Award ID
- F31AI200285
- Recipient
-
Vanderbilt University UEI GTNBNWXJ12D5
- Awarding agency
-
National Institute of Allergy and Infectious Diseases
National Institutes of Health, Department of Health and Human Services
- Obligated
- $71,112
Award facts
- Assistance listing
- 93.855 Allergy and Infectious Diseases Research
- Completion date 0% complete
- Originally
- Place of performance
- Nashville, TN 37203, USA
Award details come from USAspending.gov.
Description
- Abstract
- All domains of life require nutrient metals, such as manganese, for fundamental life processes, therefore immune-dependent metal depletion can prevent the growth of microbial pathogens in a process called nutritional immunity. Clostridioides difficile is a microbial pathogen of the gastrointestinal tract and a leading cause of hospital-acquired diarrhea. Nutritional immunity is particularly important during c. Difficile infection which leads to massive inflammation and immune-mediated metal limitation. Calprotectin is an abundant immune protein that sequesters nutrient metals and alters the transcription of c. Difficile, but its impact on host gene expression remains unclear. In addition to metal limitation, the obligate anaerobe c. Difficile must overcome exposure to oxidative stress, particularly during GUT inflammation when oxygen levels increase. To sense and respond to these stressors, c. Difficile possesses regulatory mechanisms that increase the expression of both metal transporters and enzymes that detoxify reactive oxygen species. Preliminary data suggest that inactivation of the c. Difficile protein CD196_RS17790 increases the fitness of c. Difficile in metal deplete conditions by maintaining manganese homeostasis. Manganese has redox potential and is a cofactor of c. Difficile enzymes that prevent oxidative damage, leading to the hypothesis that CD196_RS17790 contributes to the ability of c. Difficile to resist nutritional immunity and oxidative stress. A strain of c. Difficile with CD196_RS17790 inactivated (Δ17790) has been created and will be used to functionally and biochemically characterize CD196_RS17790 in aim 1. The growth of wildtype and Δ17790 c. Difficile will be assessed in metal-limited and -excess conditions as well as in the presence of H2O2. The metal-binding sites of CD196_RS17790 will be identified using computational predictions and point mutations in these residues will be made. Intracellular metal concentrations of wildtype and Δ17790 c. Difficile will be measured by inductively coupled plasma mass spectrometry. Using a murine infection model that closely models human disease, the contribution of CD196_RS17790 to c. Difficile pathogenicity will be defined. Preliminary data also revealed that mice with deficient calprotectin and infected with c. Difficile have higher transcript abundance of dual oxidase 2 (DUOX2) and its maturation factor (DUOXA2). These two proteins form the primary system for H2O2 production in the gastrointestinal tract, which may control bacterial infection, but is understudied in the context of c. Difficile infection. Combined, these findings have led to the hypothesis that increased levels of DUOX2 and DUOXA2 may reduce severity of c. Difficile infection while also damaging host gastrointestinal tissue. This will be tested in aim 2 by generation of an intestinal epithelial cell line (caco-2) with DUOX2 inactivated and infection with a fluorescent strain of c. Difficile. These infections will be imaged via super resolution microscopy. To assess the role of DUOX2 and DUOXA2 in vivo, DUOX2 inactivation and overactivation mouse lines will be infected with wildtype and Δ17790 c. Difficile. Collectively, these experiments will define the interface of nutritional immunity and oxidative stress during c. Difficile infection.
Transactions
| Action | Obligated | Date |
|---|---|---|
| Amendment | $0 | |
| Amendment | $35,556 | |
| Amendment | $0 | |
| Original award | $35,556 |
Quick answers
Who received award F31AI200285?
F31AI200285 was awarded to Vanderbilt University by National Institute of Allergy and Infectious Diseases (National Institutes of Health) on November 15, 2026.
How much is award F31AI200285 worth?
$71,112 has been obligated on F31AI200285.
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