Tumor necrosis factor-alpha (TNF) is an important cytokine regulator of the immune system. Its dysregulation is implicated in causing cancer, inflammatory bowel disease, and other systemic inflammatory disorders, including rheumatoid arthritis. TNF activity leads to the activation of pro inflammatory pathways regulated by the transcription factor NF-?B. TNF inhibitors and monoclonal antibodies are used to treat many of these autoimmune and inflammatory diseases, though with limited efficacy. Significant need exists toward improving anti-TNF based therapies. Enteric bacterial pathogens have evolved mechanisms to subvert efficiently the pro-inflammatory host defenses. Motivated by the need to discover anti-inflammatory compounds that could be developed to treat autoimmune disorders, cell-free supernatants were screened from various enteric pathogens for their ability to inhibit TNF activation of the NF-?B pathway. It was discovered that entero oxigenic Escherichia coli (ETEC) secretes a heat-stable protein that efficiently blocks the host NF-?B signaling pathway induced by TNF. This proposal will use a combination of biochemical and genetic approaches to identify this TNF antagonist and to subsequently characterize its mechanism of action.
In Specific Aim1, a combination of transposon mutagenesis, biochemical fractionation, and mass spectrometry techniques will be used to identify the TNF antagonist and the genetic locus on which it is encoded.
In Specific Aim 2, the interaction of the TNF antagonist with the host ubiquitination machinery and with NF-?B regulatory proteins will be characterized. Identifying and characterizing this ETEC protein may advance the future development of novel anti- inflammatory compounds.

Public Health Relevance

Improper regulation of tumor necrosis factor-alpha (TNF) causes systemic inflammatory disorders including rheumatoid arthritis and inflammatory bowel disease. Significant need exists toward improving anti-TNF based therapies. We are characterizing the mechanism of action of enterotoxigenic Escherichia coli proteins that antagonize the ability of TNF to activate pro-inflammatory signaling pathways.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21AI101231-02
Application #
8891351
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Rothermel, Annette L
Project Start
2014-08-01
Project End
2017-07-31
Budget Start
2015-08-01
Budget End
2017-07-31
Support Year
2
Fiscal Year
2015
Total Cost
Indirect Cost
Name
Kansas State University
Department
Veterinary Sciences
Type
Schools of Veterinary Medicine
DUNS #
929773554
City
Manhattan
State
KS
Country
United States
Zip Code
66506
Wang, Gaochan; Geisbrecht, Brian V; Rueter, Christian et al. (2017) Enterotoxigenic Escherichia coli Flagellin Inhibits TNF-Induced NF-?B Activation in Intestinal Epithelial Cells. Pathogens 6: