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Fluorescence Detection of Type III Secretion Using a Glu-CyFur Reporter System in Citrobacter rodentium
Heather A Pendergrass1, Adam L Johnson1, Julia A Hotinger1
1Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23284, USA.
Microorganisms
|December 15, 2020
Summary
A new BSL-1 assay using Citrobacter rodentium allows rapid screening of type III secretion system (T3SS) inhibitors for treating bacterial infections. This method identified EGCG and tannic acid as potent T3SS inhibitors.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Drug Discovery
Background:
- Enteropathogenic Escherichia coli (EPEC) causes infantile diarrhea globally.
- The type III secretion system (T3SS) is a key virulence factor for EPEC and Citrobacter rodentium.
- Targeting T3SS offers a therapeutic strategy without harming beneficial bacteria.
Purpose of the Study:
- To develop a safe and efficient assay for identifying T3SS inhibitors.
- To screen compounds for T3SS inhibitory activity.
- To characterize the inhibitory potential of EGCG and tannic acid.
Main Methods:
- A novel BSL-1 CPG2-reporter assay using C. rodentium was established.
- The assay does not require mammalian cell culture and is faster than Western blotting.
- Compound screening included known T3SS inhibitors and quorum sensing inhibitors.
Main Results:
- The assay effectively differentiates partial and total T3SS inhibition.
- EGCG was confirmed as a T3SS inhibitor with an IC50 of 1.8 ± 0.4 μM.
- Tannic acid demonstrated potent T3SS inhibition with an IC50 of 0.65 ± 0.09 μM.
Conclusions:
- The developed assay is a valuable tool for rapid T3SS inhibitor screening.
- EGCG and tannic acid are effective inhibitors of the bacterial T3SS.
- This research facilitates the development of novel therapeutics against EPEC infections.
