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Bahnan, Wael
Publications (5 of 5) Show all publications
Mojica, S., Eriksson, A. U., Davis, R. A., Bahnan, W., Elofsson, M. & Gylfe, Å. (2018). Red Fluorescent Chlamydia trachomatis Applied to Live Cell Imaging and Screening for Antibacterial Agents. Frontiers in Microbiology, 9, Article ID 3151.
Open this publication in new window or tab >>Red Fluorescent Chlamydia trachomatis Applied to Live Cell Imaging and Screening for Antibacterial Agents
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2018 (English)In: Frontiers in Microbiology, ISSN 1664-302X, E-ISSN 1664-302X, Vol. 9, article id 3151Article in journal (Refereed) Published
Abstract [en]

In this study, we describe the application of a transformed Chlamydia trachomatis strain constitutively expressing the red fluorescent protein mCherry, to allow real-time monitoring of the infection cycle and screening for agents that block replication of C. trachomatis. The red fluorescent C. trachomatis strain was detected autonomously without antibody staining and was equally susceptible to doxycycline as the wild type strain. A high-throughput screening assay was developed using the transformed strain and automated fluorescence microscopy. The assay was used in a pilot screen of a 349 compound library containing natural products from Australian flora and fauna. Compounds with anti-chlamydial activity were tested for dose response and toxicity to host cells and two non-toxic compounds had 50% effective concentration (EC50) values in the low micromolar range. Natural products are valuable sources for drug discovery and the identified Chlamydia growth inhibition may be starting points for future drug development. Live cell imaging was used to visualize growth of the red fluorescent C. trachomatis strain over time. The screening assay reduced workload and reagents compared to an assay requiring immunostaining and could further be used to monitor the development of Chlamydia inclusions and anti-chlamydial effect in real time.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2018
Keywords
Chlamydia trachomatis, high content screening, Australian natural products, antibacterial, anti-chlamydial, mCherry, fluorescence-based screening
National Category
Microbiology
Identifiers
urn:nbn:se:umu:diva-155099 (URN)10.3389/fmicb.2018.03151 (DOI)000453657900001 ()
Funder
Swedish Research Council
Available from: 2019-01-10 Created: 2019-01-10 Last updated: 2019-03-06Bibliographically 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
McCormack, R., Bahnan, W., Shrestha, N., Boucher, J., Barreto, M., Barrera, C. M., . . . Schesser, K. (2016). Perforin-2 Protects Host Cells and Mice by Restricting the Vacuole to Cytosol Transitioning of a Bacterial Pathogen. Infection and Immunity, 84(4), 1083-1091
Open this publication in new window or tab >>Perforin-2 Protects Host Cells and Mice by Restricting the Vacuole to Cytosol Transitioning of a Bacterial Pathogen
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2016 (English)In: Infection and Immunity, ISSN 0019-9567, E-ISSN 1098-5522, Vol. 84, no 4, p. 1083-1091Article in journal (Refereed) Published
Abstract [en]

The host-encoded Perforin-2 (encoded by the macrophage-expressed gene 1, Mpeg1), which possesses a pore-forming MACPF domain, reduces the viability of bacterial pathogens that reside within membrane-bound compartments. Here, it is shown that Perforin-2 also restricts the proliferation of the intracytosolic pathogen Listeria monocytogenes. Within a few hours of systemic infection, the massive proliferation of L. monocytogenes in Perforin-2(-/-) mice leads to a rapid appearance of acute disease symptoms. We go on to show in cultured Perforin-2(-/-) cells that the vacuole-to-cytosol transitioning of L. monocytogenes is greatly accelerated. Unexpectedly, we found that in Perforin-2(-/-) macrophages, Listeria-containing vacuoles quickly (<= 15 min) acidify, and that this was coincident with greater virulence gene expression, likely accounting for the more rapid translocation of L. monocytogenes to its replicative niche in the cytosol. This hypothesis was supported by our finding that a L. monocytogenes strain expressing virulence factors at a constitutively high level replicated equally well in Perforin-2(+/+) and Perforin-2(-/-) macrophages. Our findings suggest that the protective role of Perforin-2 against listeriosis is based on it limiting the intracellular replication of the pathogen. This cellular activity of Perforin-2 may derive from it regulating the acidification of Listeria-containing vacuoles, thereby depriving the pathogen of favorable intracellular conditions that promote its virulence gene activity.

Keywords
NNERT G, 1983, JOURNAL OF EXPERIMENTAL MEDICINE, V157, P1483 Angelo Michael E., 2012, BMC EVOLUTIONARY BIOLOGY, V12
National Category
Infectious Medicine
Identifiers
urn:nbn:se:umu:diva-123079 (URN)10.1128/IAI.01434-15 (DOI)000377103600020 ()26831467 (PubMedID)
Available from: 2016-06-27 Created: 2016-06-27 Last updated: 2018-06-07Bibliographically approved
Good, J. A. D., Silver, J., Nunez-Otero, C., Bahnan, W., Krishnan, K. S., Salin, O., . . . Almqvist, F. (2016). Thiazolino 2-Pyridone Amide Inhibitors of Chlamydia trachomatis Infectivity. Journal of Medicinal Chemistry, 59(5), 2094-2108
Open this publication in new window or tab >>Thiazolino 2-Pyridone Amide Inhibitors of Chlamydia trachomatis Infectivity
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2016 (English)In: Journal of Medicinal Chemistry, ISSN 0022-2623, E-ISSN 1520-4804, Vol. 59, no 5, p. 2094-2108Article in journal (Refereed) Published
Abstract [en]

The bacterial pathogen Chlamydia trachomatis is a global health burden currently treated with broad-spectrum antibiotics which disrupt commensal bacteria. We recently identified a compound through phenotypic screening that blocked infectivity of this intracellular pathogen without host cell toxicity (compound 1, KSK 120). Herein, we present the optimization of 1 to a class of thiazolino 2-pyridone amides that are highly efficacious (EC50 <= 100 nM) in attenuating infectivity across multiple serovars of C. trachomatis without host cell toxicity. The lead compound 21a exhibits reduced lipophilicity versus 1 and did not affect the growth or viability of representative commensal flora at 50 mu M. In microscopy studies, a highly active fluorescent analogue 37 localized inside the parasitiphorous inclusion, indicative of a specific targeting of bacterial components. In summary, we present a class of small molecules to enable the development of specific treatments for C. trachomatis.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2016
National Category
Microbiology in the medical area Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-119066 (URN)10.1021/acs.jmedchem.5b01759 (DOI)000372043400031 ()26849778 (PubMedID)
Available from: 2016-04-20 Created: 2016-04-11 Last updated: 2018-06-07Bibliographically approved
Engström, P., Bergström, M., Alfaro, A. C., Krishnan, K. S., Bahnan, W., Almqvist, F. & Bergström, S. (2015). Expansion of the Chlamydia trachomatis inclusion does not require bacterial replication. International Journal of Medical Microbiology, 305(3), 378-382
Open this publication in new window or tab >>Expansion of the Chlamydia trachomatis inclusion does not require bacterial replication
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2015 (English)In: International Journal of Medical Microbiology, ISSN 1438-4221, E-ISSN 1618-0607, Vol. 305, no 3, p. 378-382Article in journal (Refereed) Published
Abstract [en]

Chlamydia trachomatis replication takes place inside of a host cell, exclusively within a vacuole known as the inclusion. During an infection, the inclusion expands to accommodate the increasing numbers of C. trachomatis. However, whether inclusion expansion requires bacterial replication and/or de novo protein synthesis has not been previously investigated in detail. Therefore, using a chemical biology approach, we herein investigated C. trachomatis inclusion expansion under varying conditions in vitro. Under normal cell culture conditions, inclusion expansion correlated with C trachomatis replication. When bacterial replication was inhibited using KSK120: an inhibitor that targets C. trachomatis glucose metabolism, inclusions expanded even in the absence of bacterial replication. In contrast, when bacterial protein synthesis was inhibited using chloramphenicol, expansion of inclusions was blocked. Together, these data suggest that de novo protein synthesis is necessary, whereas bacterial replication is dispensable for C trachomatis inclusion expansion. (C) 2015 The Authors. Published by Elsevier GmbH.

Keywords
Chlamydia trachomatis, Chemical biology, Inclusion expansion, Bacterial replication
National Category
Microbiology in the medical area
Identifiers
urn:nbn:se:umu:diva-106141 (URN)10.1016/j.ijmm.2015.02.007 (DOI)000354583900012 ()25771502 (PubMedID)
Available from: 2015-07-13 Created: 2015-07-09 Last updated: 2018-06-07Bibliographically approved
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