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Kulén, Martina
Publications (5 of 5) Show all publications
Flentie, K., Harrison, G. A., Tükenmez, H., Livny, J., Good, J. A. D., Sarkar, S., . . . Stallings, C. L. (2019). Chemical disarming of isoniazid resistance in Mycobacterium tuberculosis. Proceedings of the National Academy of Sciences of the United States of America, 116(21), 10510-10517
Open this publication in new window or tab >>Chemical disarming of isoniazid resistance in Mycobacterium tuberculosis
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2019 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 116, no 21, p. 10510-10517Article in journal (Refereed) Published
Abstract [en]

Mycobacterium tuberculosis (Mtb) killed more people in 2017 than any other single infectious agent. This dangerous pathogen is able to withstand stresses imposed by the immune system and tolerate exposure to antibiotics, resulting in persistent infection. The global tuberculosis (TB) epidemic has been exacerbated by the emergence of mutant strains of Mtb that are resistant to frontline antibiotics. Thus, both phenotypic drug tolerance and genetic drug resistance are major obstacles to successful TB therapy. Using a chemical approach to identify compounds that block stress and drug tolerance, as opposed to traditional screens for compounds that kill Mtb, we identified a small molecule, C10, that blocks tolerance to oxidative stress, acid stress, and the frontline antibiotic isoniazid (INH). In addition, we found that C10 prevents the selection for INH-resistant mutants and restores INH sensitivity in otherwise INH-resistant Mtb strains harboring mutations in the katG gene, which encodes the enzyme that converts the prodrug INH to its active form. Through mechanistic studies, we discovered that C10 inhibits Mtb respiration, revealing a link between respiration homeostasis and INH sensitivity. Therefore, by using C10 to dissect Mtb persistence, we discovered that INH resistance is not absolute and can be reversed.

Place, publisher, year, edition, pages
The National Academy of Scionces of the United States of America, 2019
Keywords
Mycobacterium tuberculosis, drug tolerance, antibiotic resistance, isoniazid, respiration
National Category
Infectious Medicine
Identifiers
urn:nbn:se:umu:diva-159857 (URN)10.1073/pnas.1818009116 (DOI)000468403400054 ()31061116 (PubMedID)
Funder
Swedish Research CouncilKnut and Alice Wallenberg FoundationSwedish Foundation for Strategic Research The Kempe FoundationsNIH (National Institute of Health)
Available from: 2019-06-10 Created: 2019-06-10 Last updated: 2019-06-10Bibliographically approved
Kulén, M. (2018). New alternatives to combat Listeria monocytogenes and Chlamydia trachomatis: Design, synthesis, and evaluation of substituted ring-fused 2-pyridones as anti-virulent agents. (Doctoral dissertation). Umeå: Umeå universitet
Open this publication in new window or tab >>New alternatives to combat Listeria monocytogenes and Chlamydia trachomatis: Design, synthesis, and evaluation of substituted ring-fused 2-pyridones as anti-virulent agents
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Design, syntes och utvärdering av substituerade ringsammansatta 2-pyridoner med biologisk aktivitet mot Listeria monocytogenes och Chlamydia trachomatis
Abstract [en]

Antibiotic resistance has become a global health burden with the number of resistant bacteria continuously increasing. Antibiotic drugs act by being either bactericidal (killing bacteria) or bacteriostatic (inhibiting growth of bacteria). However, these modes of action increase the selective pressure on the bacteria. An alternative treatment strategy to antibiotics is anti-virulence therapies that inhibits virulence of the pathogenic bacteria. The term “virulence” summarises a number of factors that the bacteria need to colonise a new niche and as a consequence its ability to infect and cause diseases. By inhibiting virulence, instead of killing, the selective pressure on the bacteria can be reduced and consequently decreases the rapid development of resistance. This thesis describes two projects focusing on development of anti-virulence agents, with the ring-fused 2-pyridone scaffold as the central character, targeting the bacteria Listeria monocytogenes and Chlamydia trachomatis.

The first project is targeting L. monocytogenes, which is the cause for listeriosis in humans. This can develop into life-threatening encephalitis and meningitis as well as cause severe complications for developing fetus. The target in L. monocytogenes is the transcriptional regulator PrfA that control almost all virulence factors in this bacterium. We have designed and synthesised potent substituted ring-fused 2-pyridones, which at low micromolar concentrations block activation of the virulence regulator PrfA and thus attenuate the bacterial infection. Co-crystallisation of the active ring-fused 2-pyridones with PrfA resulted in determination of the exact substance interaction site in the protein. This facilitated further structure-based design that resulted in improved compounds capable of attenuating L. monocytogenes in an in vivo model.

The second project targets C. trachomatis, which is the causative agent behind the most common sexually transmitted infection as well as the eye infection trachoma. By structure-activity relationship analysis of previously tested ring-fused 2-pyridones, we have designed and synthesised non-hydrolysable ring-fused 2-pyridone amide isosteres. The most potent analogues inhibit C. trachomatis infectivity at low nanomolar concentrations, without showing host cell toxicity or affecting the viability of commensal microbiota. Introduction of heteroatom substituents at specific sites of the ring-fused 2-pyridone scaffold, resulted in improved pharmacokinetic properties of the analogues and further evaluation in vivo was performed.

Place, publisher, year, edition, pages
Umeå: Umeå universitet, 2018. p. 86
Keywords
Antibiotic resistance, anti-virulence, Listeria monocytogenes, Chlamydia trachomatis, ring-fused 2-pyridone, organic synthesis, structure-based design, PrfA, drug design, structure-activity relationship
National Category
Organic Chemistry
Identifiers
urn:nbn:se:umu:diva-151128 (URN)978-91-7601-920-7 (ISBN)
Public defence
2018-09-21, KB.E3.03 (Stora hörsalen), KBC-huset, Umeå, 09:00 (English)
Opponent
Supervisors
Available from: 2018-08-31 Created: 2018-08-28 Last updated: 2018-08-29Bibliographically approved
Kulén, M., Lindgren, M., Hansen, S., Cairns, A. G., Grundström, C., Begum, A., . . . Almqvist, F. (2018). Structure-based design of inhibitors targeting PrfA, the master virulence regulator of Listeria monocytogenes. Journal of Medicinal Chemistry, 61(9), 4165-4175
Open this publication in new window or tab >>Structure-based design of inhibitors targeting PrfA, the master virulence regulator of Listeria monocytogenes
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2018 (English)In: Journal of Medicinal Chemistry, ISSN 0022-2623, E-ISSN 1520-4804, Vol. 61, no 9, p. 4165-4175Article in journal (Refereed) Published
Abstract [en]

Listeria monocytogenes is a bacterial pathogen that controls much of its virulence through the transcriptional regulator PrfA. In this study, we describe structure guided design and synthesis of a set of PrfA inhibitors based on ring-fused 2-pyridone heterocycles. Our most effective compound decreased virulence factor expression, reduced bacterial uptake into eukaryotic cells, and improved survival of chicken embryos infected with L. monocytogenes compared to previously identified compounds. Crystal structures identified an intraprotein "tunnel" as the main inhibitor binding site (A1), where the compounds participate in an extensive hydrophobic network that restricts the protein's ability to form functional DNA-binding helix−turn−helix (HTH) motifs. Our studies also revealed a hitherto unsuspected structural plasticity of the HTH motif. In conclusion, we have designed 2-pyridone analogues that function as site-A1 selective PrfA inhibitors with potent antivirulence properties.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Medicinal Chemistry
Identifiers
urn:nbn:se:umu:diva-148830 (URN)10.1021/acs.jmedchem.8b00289 (DOI)000432204800027 ()29667825 (PubMedID)2-s2.0-85046422455 (Scopus ID)
Available from: 2018-06-13 Created: 2018-06-13 Last updated: 2018-08-28Bibliographically approved
Good, J. A. D., Kulén, M., Silver, J., Krishnan, K. S., Bahnan, W., Núñez-Otero, C., . . . Almqvist, F. (2017). Thiazolino 2-pyridone amide isosteres as inhibitors of Chlamydia trachomatis infectivity. Journal of Medicinal Chemistry, 60(22), 9393-9399
Open this publication in new window or tab >>Thiazolino 2-pyridone amide isosteres as inhibitors of Chlamydia trachomatis infectivity
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2017 (English)In: Journal of Medicinal Chemistry, ISSN 0022-2623, E-ISSN 1520-4804, Vol. 60, no 22, p. 9393-9399Article in journal (Refereed) Published
Abstract [en]

Chlamydia trachomatis is a global health burden due to its prevalence as a sexually transmitted disease and as the causative agent of the eye infection trachoma. We recently discovered 3-amido thiazolino 2-pyridones which attenuated C. trachomatis infectivity without affecting host cell or commensal bacteria viability. We present here the synthesis and evaluation of nonhydrolyzable amide isosteres based on this class, leading to highly potent 1,2,3-triazole based infectivity inhibitors (EC50 ≤ 20 nM).

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2017
National Category
Medicinal Chemistry
Identifiers
urn:nbn:se:umu:diva-142974 (URN)10.1021/acs.jmedchem.7b00716 (DOI)000416500200019 ()29053275 (PubMedID)
Available from: 2017-12-14 Created: 2017-12-14 Last updated: 2018-08-28Bibliographically approved
Kulén, M., Núñez-Otero, C., Cairns, A. G., Silver, J., Lindgren, A. E. G., Wede, E., . . . Almqvist, F.Design, Synthesis, and Evaluation of Chlamydia trachomatis Infectivity Inhibitors with Improved Pharmacokintetic Properties.
Open this publication in new window or tab >>Design, Synthesis, and Evaluation of Chlamydia trachomatis Infectivity Inhibitors with Improved Pharmacokintetic Properties
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(English)Manuscript (preprint) (Other academic)
National Category
Organic Chemistry
Identifiers
urn:nbn:se:umu:diva-151127 (URN)
Available from: 2018-08-28 Created: 2018-08-28 Last updated: 2018-08-28
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