umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Chemical attenuation of bacterial virulence: small molecule inhibitors of type III secretion
Umeå University, Faculty of Science and Technology, Department of Chemistry.
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Despite the large arsenal of antibiotics available on the market, treatment of bacterial infections becomes more challenging in view of the fact that microbes develop resistance against existing drugs. There is an obvious need for novel drugs acting on both old and new targets in bacteria. In this thesis we have employed a whole cell bacterial assay for screening and identification of type III secretion system (T3SS) inhibitors in Yersinia pseudotuberculosis. The T3SS is a common virulence mechanism utilized by several clinically relevant Gram-negative bacteria including Salmonella, Shigella, Pseudomonas aeruginosa, Chlamydiae and Escherichia coli. Several components in the T3SS have proved to be conserved and hence data generated with Y. pseudotuberculosis as model might also be valid for other bacterial species.

We have screened a 9,400 commercial compound library for T3S inhibitors in Y. pseudotuberculosis using a yopE reporter gene assay. The initial ~ 30 hits were followed up in a growth inhibition assay resulting in 26 interesting compounds that were examined in more detail. Three of the most interesting compounds, salicylanilides, 2-hydroxybenzylidene-hydrazides and 2-arylsulfonamino-benzanilides, were selected for continued investigations. The inhibitor classes show different profiles regarding the effects on T3SS in Yersinia and their use as research tools and identification of the target proteins using a chemical biology approach will increase our understanding of bacterial virulence.

The 2-hydroxybenzylidene-hydrazides have been extensively studied in vitro and show potential as selective T3S inhibitors in several Gram-negative pathogens besides Y. pseudotuberculosis. The data obtained suggest that this inhibitor class targets a conserved protein in the secretion apparatus. In cell-based ex vivo infection models T3SS was inhibited to the advantage of the infected eukaryotic cells. The salicylanilides and 2-arylsulfonamino-benzanilides have been further investigated by statistical molecular design (SMD) followed by synthesis and biological evaluation in the T3SS linked reporter gene assay. Multivariate QSAR models were established despite the challenges with data obtained from assays using viable bacteria. Our results indicate that this SMD QSAR strategy is powerful in development of virulence inhibitors targeting the T3SS.

Place, publisher, year, edition, pages
Umeå: Kemi , 2006. , 73 p.
Keyword [en]
antibiotic resistance, virulence, type III secretion, T3SS inhibitors, Yop, SMD, QSAR, screening, Yersinia pseudotuberculosis
National Category
Organic Chemistry
Identifiers
URN: urn:nbn:se:umu:diva-936ISBN: 91-7264-178-9 (print)OAI: oai:DiVA.org:umu-936DiVA: diva2:145112
Public defence
2006-12-08, KB3B1, KBC-huset, Linneaus vägen 10, Umeå Universitet, 90187 Umeå, 10:00 (English)
Opponent
Supervisors
Available from: 2006-11-17 Created: 2006-11-17 Last updated: 2011-12-21Bibliographically approved
List of papers
1. Targeting bacterial Virulence:  Inhibitors of type III secretion in Yersinia
Open this publication in new window or tab >>Targeting bacterial Virulence:  Inhibitors of type III secretion in Yersinia
Show others...
2003 (English)In: Chemistry and Biology, ISSN 1074-5521, E-ISSN 1879-1301, Vol. 10, no 3, 241-249 p.Article in journal (Refereed) Published
Abstract [en]

Agents that target bacterial virulence without detrimental effect on bacterial growth are useful chemical probes for studies of virulence and potential candidates for drug development. Several gram-negative pathogens employ type III secretion to evade the innate immune response of the host. Screening of a chemical library with a luciferase reporter gene assay in viable Yersinia pseudotuberculosis furnished several compounds that inhibit the reporter gene signal expressed from the yopE promoter and effector protein secretion at concentrations with no or modest effect on bacterial growth. The selectivity patterns observed for inhibition of various reporter gene strains indicate that the compounds target the type III secretion machinery at different levels. Identification of this set of inhibitors illustrates the approach of utilizing cell-based assays to identify compounds that affect complex bacterial virulence systems.

Identifiers
urn:nbn:se:umu:diva-10053 (URN)doi:10.1016/S1074-5521(03)00046-2 (DOI)
Available from: 2008-06-11 Created: 2008-06-11 Last updated: 2017-12-14Bibliographically approved
2. Small-molecule inhibitors specifically targeting type III secretion
Open this publication in new window or tab >>Small-molecule inhibitors specifically targeting type III secretion
Show others...
2005 (English)In: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 73, no 5, 3104-3114 p.Article in journal (Refereed) Published
Abstract [en]

The type III secretion (TTS) system is used by several animal and plant pathogens to deliver effector proteins into the cytosol of the eukaryotic target cell as a strategy to evade the defense reactions elicited by the infected organism. The fact that these systems are highly homologous implies that novel antibacterial agents that chemically attenuate the pathogens via a specific interaction with the type III secretion mechanism can be identified. A number of small organic molecules having this potential have recently been identified (A. M. Kauppi, R. Nordfelth, H. Uvell, H. Wolf-Watz, and M. Elofsson, Chem. Biol. 10:241-249, 2003). Using different reporter gene constructs, we showed that compounds that belong to a class of acylated hydrazones of different salicylaldehydes target the TTS system of Yersinia pseudotuberculosis. One of these compounds, compound 1, was studied in detail and was found to specifically block Yop effector secretion under in vitro conditions by targeting the TTS system. In this respect the drug mimics the well-known effect of calcium on Yop secretion. In addition, compound I inhibits Yop effector translocation after infection of HeLa cells without affecting the eukaryotic cells or the bacteria. A HeLa cell model that mimics in vivo conditions showed that compound 1 chemically attenuates the pathogen to the advantage of the eukaryotic cell. Thus, our results show proof of concept, i.e., that small compounds targeting the TTS system can be identified, and they point to the possible use of TTS inhibitors as a novel class of antibacterial agents.

Place, publisher, year, edition, pages
Washington: American Society for Microbiology, 2005
Keyword
low-calcium response, yersinia-pseudotuberculosis, antimicrobial chemotherapy, functional conservation, multidrug-resistance, bacterial virulence, escherichia-coli, plasma-membrane, cell contact, protein
Identifiers
urn:nbn:se:umu:diva-13079 (URN)doi:10.1128/IAI.73.5.3104-3114.2005 (DOI)
Available from: 2007-05-02 Created: 2007-05-02 Last updated: 2017-12-14Bibliographically approved
3. Inhibitors of type III secretion in Yersinia: design, synthesis and multivariate QSAR of 2-sulfonamino-benzanilides
Open this publication in new window or tab >>Inhibitors of type III secretion in Yersinia: design, synthesis and multivariate QSAR of 2-sulfonamino-benzanilides
Show others...
2007 (English)In: Bioorganic & Medicinal Chemistry, ISSN 0968-0896, E-ISSN 1464-3391, Vol. 15, no 22, 6994-7011 p.Article in journal (Other academic) Published
Abstract [en]

Compound 1, 2-(benzo[1,2,5]thiadiazole-4-sulfonylamino)-5-chloro-N-(3,4-dichloro-phenyl)-benzamide, was identified as a putative type III secretion inhibitor in Yersinia, and the compound thus has a potential to be used to prevent or treat bacterial infections. A set of seven analogues was synthesized and evaluated in a type III secretion dependent reporter-gene assay with viable bacterial to give basic SAR. A second set of 19 compounds was obtained by statistical molecular design in the building block and product space and subsequent synthesis. Evaluation in the reporter-gene assay showed that the compounds ranged from non-active to compounds more potent than 1. Based on the data multivariate QSAR models were established and the final Hi-PLS model showed good correlation between experimentally determined % inhibition and the calculated % inhibition of the reporter-gene signal.

Place, publisher, year, edition, pages
Elsevier Ltd, 2007
Keyword
Type III secretion, Yersinia, Virulence, Inhibitors, Statistical molecular design: multivariate QSAR
National Category
Organic Chemistry
Identifiers
urn:nbn:se:umu:diva-5559 (URN)10.1016/j.bmc.2007.07.047 (DOI)
Note
Available online 22 August 2007 Available from: 2006-11-17 Created: 2006-11-17 Last updated: 2017-12-14Bibliographically approved
4. Salicylanilides are potent inhibitors of type III in Yersinia
Open this publication in new window or tab >>Salicylanilides are potent inhibitors of type III in Yersinia
Show others...
2003 In: Advances in experimental medicine and biology, ISSN 0065-2598, Vol. 529, 97-100 p.Article in journal (Refereed) Published
Identifiers
urn:nbn:se:umu:diva-5560 (URN)
Available from: 2006-11-17 Created: 2006-11-17Bibliographically approved

Open Access in DiVA

fulltext(2693 kB)1556 downloads
File information
File name FULLTEXT01.pdfFile size 2693 kBChecksum SHA-1
1a7b5b648ba9eafdd9c3c5e78574468ee13bdea71a3764dc0113f208d5b72f64d72d68a3
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Kauppi, Anna
By organisation
Department of Chemistry
Organic Chemistry

Search outside of DiVA

GoogleGoogle Scholar
Total: 1556 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 835 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf