Fluorescence Detection of Type III Secretion Using a Glu-CyFur Reporter System in <i>Citrobacter rodentium</i>
Enteropathogenic <i>Escherichia coli</i> (EPEC) is a major cause of infantile diarrhea worldwide. EPEC and the closely related murine model of EPEC infection, <i>Citrobacter rodentium</i>, utilize a type III secretion system (T3SS) to propagate the infection. Since the T3SS i...
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MDPI AG
2020-12-01
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| Series: | Microorganisms |
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| Online Access: | https://www.mdpi.com/2076-2607/8/12/1953 |
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| author | Heather A. Pendergrass Adam L. Johnson Julia A. Hotinger Aaron E. May |
| author_facet | Heather A. Pendergrass Adam L. Johnson Julia A. Hotinger Aaron E. May |
| author_sort | Heather A. Pendergrass |
| collection | DOAJ |
| description | Enteropathogenic <i>Escherichia coli</i> (EPEC) is a major cause of infantile diarrhea worldwide. EPEC and the closely related murine model of EPEC infection, <i>Citrobacter rodentium</i>, utilize a type III secretion system (T3SS) to propagate the infection. Since the T3SS is not essential for the bacteria to survive or propagate, inhibiting the virulence factor with a therapeutic would treat the infection without causing harm to commensal bacteria. Studying inhibitors of the T3SS usually requires a BSL-2 laboratory designation and eukaryotic host cells while not indicating the mechanism of inhibition. We have designed a BSL-1 assay using the murine model <i>C. rodentium</i> that does not require mammalian cell culture. This CPG2-reporter assay allows for more rapid analysis of secretion efficiency than Western blotting and is sensitive enough to differentiate between partial and total inhibition of the T3SS. Here we present our method and the results of a small collection of compounds we have screened, including known T3SS inhibitors EGCG, regacin, and aurodox and related quorum sensing inhibitors tannic acid and ellagic acid. We have further characterized EGCG as a T3SS inhibitor and established its IC<sub>50</sub> of 1.8 ± 0.4 μM. We also establish tannic acid as a potent inhibitor of the T3SS with an IC<sub>50</sub> of 0.65 ± 0.09 μM. |
| first_indexed | 2024-03-10T14:13:20Z |
| format | Article |
| id | doaj.art-17de26ecb44d4f66bc2f79da3ca53f61 |
| institution | Directory Open Access Journal |
| issn | 2076-2607 |
| language | English |
| last_indexed | 2024-03-10T14:13:20Z |
| publishDate | 2020-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Microorganisms |
| spelling | doaj.art-17de26ecb44d4f66bc2f79da3ca53f612023-11-20T23:59:47ZengMDPI AGMicroorganisms2076-26072020-12-01812195310.3390/microorganisms8121953Fluorescence Detection of Type III Secretion Using a Glu-CyFur Reporter System in <i>Citrobacter rodentium</i>Heather A. Pendergrass0Adam L. Johnson1Julia A. Hotinger2Aaron E. May3Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23284, USADepartment of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23284, USADepartment of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23284, USADepartment of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23284, USAEnteropathogenic <i>Escherichia coli</i> (EPEC) is a major cause of infantile diarrhea worldwide. EPEC and the closely related murine model of EPEC infection, <i>Citrobacter rodentium</i>, utilize a type III secretion system (T3SS) to propagate the infection. Since the T3SS is not essential for the bacteria to survive or propagate, inhibiting the virulence factor with a therapeutic would treat the infection without causing harm to commensal bacteria. Studying inhibitors of the T3SS usually requires a BSL-2 laboratory designation and eukaryotic host cells while not indicating the mechanism of inhibition. We have designed a BSL-1 assay using the murine model <i>C. rodentium</i> that does not require mammalian cell culture. This CPG2-reporter assay allows for more rapid analysis of secretion efficiency than Western blotting and is sensitive enough to differentiate between partial and total inhibition of the T3SS. Here we present our method and the results of a small collection of compounds we have screened, including known T3SS inhibitors EGCG, regacin, and aurodox and related quorum sensing inhibitors tannic acid and ellagic acid. We have further characterized EGCG as a T3SS inhibitor and established its IC<sub>50</sub> of 1.8 ± 0.4 μM. We also establish tannic acid as a potent inhibitor of the T3SS with an IC<sub>50</sub> of 0.65 ± 0.09 μM.https://www.mdpi.com/2076-2607/8/12/1953EPECEHEC<i>C. rodentium</i>T3SSpathogenesisnatural products |
| spellingShingle | Heather A. Pendergrass Adam L. Johnson Julia A. Hotinger Aaron E. May Fluorescence Detection of Type III Secretion Using a Glu-CyFur Reporter System in <i>Citrobacter rodentium</i> Microorganisms EPEC EHEC <i>C. rodentium</i> T3SS pathogenesis natural products |
| title | Fluorescence Detection of Type III Secretion Using a Glu-CyFur Reporter System in <i>Citrobacter rodentium</i> |
| title_full | Fluorescence Detection of Type III Secretion Using a Glu-CyFur Reporter System in <i>Citrobacter rodentium</i> |
| title_fullStr | Fluorescence Detection of Type III Secretion Using a Glu-CyFur Reporter System in <i>Citrobacter rodentium</i> |
| title_full_unstemmed | Fluorescence Detection of Type III Secretion Using a Glu-CyFur Reporter System in <i>Citrobacter rodentium</i> |
| title_short | Fluorescence Detection of Type III Secretion Using a Glu-CyFur Reporter System in <i>Citrobacter rodentium</i> |
| title_sort | fluorescence detection of type iii secretion using a glu cyfur reporter system in i citrobacter rodentium i |
| topic | EPEC EHEC <i>C. rodentium</i> T3SS pathogenesis natural products |
| url | https://www.mdpi.com/2076-2607/8/12/1953 |
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