C. difficile colitis is a toxin-mediated disease, which is dependent on the actions of Toxin A (TcdA) and/or Toxin B (TcdB). Although the molecular mechanisms by which TcdA and TcdB modify Rho-subfamily GTPases are well defined, the pathways connecting those events to colitis and inflammatory diarrhea remain elusive. In this sub-project of MARCE Research Program V (Interactions of Select Agent Toxins and Toxins of Emerging Bacterial Pathogens with Host Cells), we will combine the analytical methods of systems biology with expression profiles (gene expression and protein modification) and associated biological consequences, in order to elucidate the pathways affected by the specific toxin-mediated glucosylation of one or more small GTPases. Cultured human cells alone and in combinations (intestinal epithelium and other cell types directly affected by the toxins) will be studied in vitro and mouse ligated ileal loops will be studied in vivo to characterize the phenotypes induced by the toxins and to determine the optimal conditions for collection of the gene array data. A novel pathway-based compendium analysis will be used to overlay the in vitro and in vivo transcriptional profiles on a literature-derived pathway knowledge database, thereby identifying signaling networks altered by the toxins (SA 1). Concurrently, data derived through gene expression arrays will be validated using qRT-PCR, Western blotting, phospho-protein analyses and in situ hybridization. Partial least-squares regression analysis will be applied to the collective data, in order to characterize the key signaling metrics for the phenotypes elicited by TcdA and TcdB (SA 2). New hypotheses will then be generated and tested by making biological and biochemical manipulations of the newly recognized pathways and signaling molecules and determining the biological consequences with and without the toxins (SA 3). This exciting project reflects a close interaction of three groups, representing: 1) microbial toxin action and molecular pathogenesis (Hewlett);2) pathogenesis of diseases caused by enteric pathogens and enterotoxins (Guerrant and Warren) and 3) systems bioengineering in infectious diseases (Papin).

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Specialized Center--Cooperative Agreements (U54)
Project #
5U54AI057168-10
Application #
8442376
Study Section
Special Emphasis Panel (ZAI1-DDS-M)
Project Start
Project End
2015-02-28
Budget Start
2013-03-01
Budget End
2015-02-28
Support Year
10
Fiscal Year
2013
Total Cost
$279,485
Indirect Cost
$33,931
Name
University of Maryland Baltimore
Department
Type
DUNS #
188435911
City
Baltimore
State
MD
Country
United States
Zip Code
21201
Freedman, John C; Theoret, James R; Wisniewski, Jessica A et al. (2015) Clostridium perfringens type A-E toxin plasmids. Res Microbiol 166:264-79
Li, Jihong; McClane, Bruce A (2014) Contributions of NanI sialidase to Caco-2 cell adherence by Clostridium perfringens type A and C strains causing human intestinal disease. Infect Immun 82:4620-30
Moy, Ryan H; Gold, Beth; Molleston, Jerome M et al. (2014) Antiviral autophagy restrictsRift Valley fever virus infection and is conserved from flies to mammals. Immunity 40:51-65
Cuevas, Christian D; Ross, Susan R (2014) Toll-like receptor 2-mediated innate immune responses against Junín virus in mice lead to antiviral adaptive immune responses during systemic infection and do not affect viral replication in the brain. J Virol 88:7703-14
Boyd, Mary Adetinuke; Tennant, Sharon M; Saague, Venant A et al. (2014) Serum bactericidal assays to evaluate typhoidal and nontyphoidal Salmonella vaccines. Clin Vaccine Immunol 21:712-21
Su, Yi-Hsuan; Tsegaye, Mikiyas; Varhue, Walter et al. (2014) Quantitative dielectrophoretic tracking for characterization and separation of persistent subpopulations of Cryptosporidium parvum. Analyst 139:66-73
Xu, Jie; Cherry, Sara (2014) Viruses and antiviral immunity in Drosophila. Dev Comp Immunol 42:67-84
Uzal, Francisco A; Freedman, John C; Shrestha, Archana et al. (2014) Towards an understanding of the role of Clostridium perfringens toxins in human and animal disease. Future Microbiol 9:361-77
Weir, Dawn L; Laing, Eric D; Smith, Ina L et al. (2014) Host cell virus entry mediated by Australian bat lyssavirus G envelope glycoprotein occurs through a clathrin-mediated endocytic pathway that requires actin and Rab5. Virol J 11:40
Weir, Dawn L; Annand, Edward J; Reid, Peter A et al. (2014) Recent observations on Australian bat lyssavirus tropism and viral entry. Viruses 6:909-26

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