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Saleeb, Michael
Publications (9 of 9) Show all publications
Massai, F., Saleeb, M., Doruk, T., Elofsson, M. & Forsberg, Å. (2019). Development, Optimization, and Validation of a High Throughput Screening Assay for Identification of Tat and Type II Secretion Inhibitors of Pseudomonas aeruginosa. Frontiers in Cellular and Infection Microbiology, 9, Article ID 250.
Open this publication in new window or tab >>Development, Optimization, and Validation of a High Throughput Screening Assay for Identification of Tat and Type II Secretion Inhibitors of Pseudomonas aeruginosa
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2019 (English)In: Frontiers in Cellular and Infection Microbiology, E-ISSN 2235-2988, Vol. 9, article id 250Article in journal (Refereed) Published
Abstract [en]

Antibiotics are becoming less effective in treatment of infections caused by multidrug-resistant Pseudomonas aeruginosa. Antimicrobial therapies based on the inhibition of specific virulence-related traits, as opposed to growth inhibitors, constitute an innovative and appealing approach to tackle the threat of P. aeruginosa infections. The twin-arginine translocation (Tat) pathway plays an important role in the pathogenesis of P. aeruginosa, and constitutes a promising target for the development of anti-pseudomonal drugs. In this study we developed and optimized a whole-cell, one-well assay, based on native phospholipase C activity, to identify compounds active against the Tat system. Statistical robustness, sensitivity and consequently suitability for high-throughput screening (HTS) were confirmed by a dry run/pre-screening test scoring a Z' of 0.82 and a signal-to-noise ratio of 49. Using this assay, we evaluated ca. 40,000 molecules and identified 59 initial hits as possible Tat inhibitors. Since phospholipase C is exported into the periplasm by Tat, and subsequently translocated across the outer membrane by the type II secretion system (T2SS), our assay could also identify T2SS inhibitors. To validate our hits and discriminate between compounds that inhibited either Tat or T2SS, two separate counter assays were developed and optimized. Finally, three Tat inhibitors and one T2SS inhibitor were confirmed by means of dose-response analysis and additional counter and confirming assays. Although none of the identified inhibitors was suitable as a lead compound for drug development, this study validates our assay as a simple, efficient, and HTS compatible method for the identification of Tat and T2SS inhibitors.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2019
Keywords
Pseudomonas aeruginosa, high-throughput screening, twin arginine translocase, type II secretion, virulence inhibitors, phospholipase C
National Category
Infectious Medicine
Identifiers
urn:nbn:se:umu:diva-161822 (URN)10.3389/fcimb.2019.00250 (DOI)000474778200001 ()31355152 (PubMedID)
Available from: 2019-08-13 Created: 2019-08-13 Last updated: 2019-08-13Bibliographically approved
Islam, M. K. K., Strand, M., Saleeb, M., Svensson, R., Baranczewski, P., Artursson, P., . . . Evander, M. (2018). Anti-Rift Valley fever virus activity in vitro, pre-clinical pharmacokinetics and oral bioavailability of benzavir-2, a broad-acting antiviral compound. Scientific Reports, 8, Article ID 1925.
Open this publication in new window or tab >>Anti-Rift Valley fever virus activity in vitro, pre-clinical pharmacokinetics and oral bioavailability of benzavir-2, a broad-acting antiviral compound
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2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 1925Article in journal (Refereed) Published
Abstract [en]

Rift Valley fever virus (RVFV) is a mosquito-borne hemorrhagic fever virus affecting both humans and animals with severe morbidity and mortality and is classified as a potential bioterror agent due to the possible aerosol transmission. At present there is no human vaccine or antiviral therapy available. Thus, there is a great need to develop new antivirals for treatment of RVFV infections. Benzavir-2 was previously identified as potent inhibitor of human adenovirus, herpes simplex virus type 1, and type 2. Here we assess the anti-RVFV activity of benzavir-2 together with four structural analogs and determine pre-clinical pharmacokinetic parameters of benzavir-2. In vitro, benzavir-2 efficiently inhibited RVFV infection, viral RNA production and production of progeny viruses. In vitro, benzavir-2 displayed satisfactory solubility, good permeability and metabolic stability. In mice, benzavir-2 displayed oral bioavailability with adequate maximum serum concentration. Oral administration of benzavir-2 formulated in peanut butter pellets gave high systemic exposure without any observed toxicity in mice. To summarize, our data demonstrated potent anti-RVFV activity of benzavir-2 in vitro together with a promising pre-clinical pharmacokinetic profile. This data support further exploration of the antiviral activity of benzavir-2 in in vivo efficacy models that may lead to further drug development for human use.

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2018
National Category
Microbiology in the medical area
Identifiers
urn:nbn:se:umu:diva-144950 (URN)10.1038/s41598-018-20362-9 (DOI)000423663100004 ()29386590 (PubMedID)
Available from: 2018-02-22 Created: 2018-02-22 Last updated: 2018-09-14Bibliographically approved
Kumar, A., Saleeb, M., Werz, D. & Elofsson, M. (2018). Cyclopropylmethyl Protection of Phenols: Total Synthesis of the Resveratrol Dimers Anigopreissin A and Resveratrol-Piceatannol Hybrid. ChemistryOpen, 7(12), 953-956
Open this publication in new window or tab >>Cyclopropylmethyl Protection of Phenols: Total Synthesis of the Resveratrol Dimers Anigopreissin A and Resveratrol-Piceatannol Hybrid
2018 (English)In: ChemistryOpen, ISSN 2191-1363, Vol. 7, no 12, p. 953-956Article in journal (Refereed) Published
Abstract [en]

We demonstrate the versatile use of the cyclopropylmethyl group to protect phenols through the total synthesis of two benzofuran-based natural products, that is, anigopreissin A and the resveratrol-piceatannol hybrid. This protecting group is a good alternative to the conventional methyl group, owing to the feasibility of introduction, stability under a variety of conditions, and its relative ease of removal under different acidic conditions.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2018
Keywords
anigopreissin A, cyclopropylmethyl protecting group, deprotection, resveratrol-piceatannol hybrid, total synthesis
National Category
Organic Chemistry
Identifiers
urn:nbn:se:umu:diva-155651 (URN)10.1002/open.201800214 (DOI)000454525600002 ()30524921 (PubMedID)
Funder
Swedish Research Council, 621-2014-4670
Available from: 2019-01-25 Created: 2019-01-25 Last updated: 2019-01-25Bibliographically approved
Saleeb, M., Mojica, S., Eriksson, A. U., Andersson, C. D., Gylfe, Å. & Elofsson, M. (2018). Natural product inspired library synthesis – Identification of 2,3-diarylbenzofuran and 2,3-dihydrobenzofuran based inhibitors of Chlamydia trachomatis. European Journal of Medicinal Chemistry, 143, 1077-1089
Open this publication in new window or tab >>Natural product inspired library synthesis – Identification of 2,3-diarylbenzofuran and 2,3-dihydrobenzofuran based inhibitors of Chlamydia trachomatis
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2018 (English)In: European Journal of Medicinal Chemistry, ISSN 0223-5234, E-ISSN 1768-3254, Vol. 143, p. 1077-1089Article in journal (Refereed) Published
Abstract [en]

A natural product inspired library was synthesized based on 2,3-diarylbenzofuran and 2,3-diaryl-2,3-dihydrobenzofuran scaffolds. The library of forty-eight compounds was prepared by utilizing Pd-catalyzed one-pot multicomponent reactions and ruthenium-catalyzed intramolecular carbenoid C-H insertions. The compounds were evaluated for antibacterial activity in a panel of test systems including phenotypic, biochemical and image-based screening assays. We identified several potent inhibitors that block intracellular replication of pathogenic Chlamydia trachomatis with IC50 ≤ 3 μM. These new C. trachomatis inhibitors can serve as starting points for the development of specific treatments that reduces the global burden of C. trachomatis infections.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
2, 3-diaryl-2, 3-dihydrobenzofuran, 2, 3-diaryl-benzofuran, Antibacterial, Benzofuran, Chlamydia
National Category
Organic Chemistry Biological Sciences
Identifiers
urn:nbn:se:umu:diva-143062 (URN)10.1016/j.ejmech.2017.11.099 (DOI)000428216700089 ()29232584 (PubMedID)
Funder
Swedish Foundation for Strategic Research , SB12-0022Swedish Research Council, 621-2014-4670
Available from: 2017-12-18 Created: 2017-12-18 Last updated: 2018-08-24Bibliographically approved
Saleeb, M., Sundin, C., Aglar, Ö., Pinto, A. F., Ebrahimi, M., Forsberg, Å., . . . Elofsson, M. (2018). Structure–activity relationships for inhibitors of Pseudomonas aeruginosa exoenzyme S ADP-ribosyltransferase activity. European Journal of Medicinal Chemistry, 143, 568-576
Open this publication in new window or tab >>Structure–activity relationships for inhibitors of Pseudomonas aeruginosa exoenzyme S ADP-ribosyltransferase activity
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2018 (English)In: European Journal of Medicinal Chemistry, ISSN 0223-5234, E-ISSN 1768-3254, Vol. 143, p. 568-576Article in journal (Refereed) Published
Abstract [en]

During infection, the Gram-negative opportunistic pathogen Pseudomonas aeruginosa employs its type III secretion system to translocate the toxin exoenzyme S (ExoS) into the eukaryotic host cell cytoplasm. ExoS is an essential in vivo virulence factor that enables P. aeruginosa to avoid phagocytosis and eventually kill the host cell. ExoS elicits its pathogenicity mainly via ADP-ribosyltransferase (ADPRT) activity. We recently identified a new class of ExoS ADPRT inhibitors with in vitro IC50 of around 20 μM in an enzymatic assay using a recombinant ExoS ADPRT domain. Herein, we report structure-activity relationships of this compound class by comparing a total of 51 compounds based on a thieno [2,3-d]pyrimidin-4(3H)-one and 4-oxo-3,4-dihydroquinazoline scaffolds. Improved inhibitors with in vitro IC50 values of 6 μM were identified. Importantly, we demonstrated that the most potent inhibitors block ADPRT activity of native full-length ExoS secreted by viable P. aeruginosa with an IC50 value of 1.3 μM in an enzymatic assay. This compound class holds promise as starting point for development of novel antibacterial agents.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
2-Aminobenzamide, ADP-Ribosyltransferase, Bacterial exotoxins, ExoS, Pseudomonas aeruginosa, Quinazolines, Type III secretion
National Category
Organic Chemistry Cell and Molecular Biology
Identifiers
urn:nbn:se:umu:diva-143429 (URN)10.1016/j.ejmech.2017.11.036 (DOI)000428216700046 ()29207339 (PubMedID)
Available from: 2017-12-23 Created: 2017-12-23 Last updated: 2018-08-24Bibliographically approved
Krzyzanowski, A., Saleeb, M. & Elofsson, M. (2018). Synthesis of Indole-, Benzo[ b]thiophene-, and Benzo[ b]selenophene-Based Analogues of the Resveratrol Dimers Viniferifuran and (±)-Dehydroampelopsin B.. Organic Letters, 20(21), 6650-6654
Open this publication in new window or tab >>Synthesis of Indole-, Benzo[ b]thiophene-, and Benzo[ b]selenophene-Based Analogues of the Resveratrol Dimers Viniferifuran and (±)-Dehydroampelopsin B.
2018 (English)In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 20, no 21, p. 6650-6654Article in journal (Refereed) Published
Abstract [en]

A convenient synthetic strategy to obtain viniferifuran and (±)-dehydroampelopsin B analogues based on the heterocyclic cores of indole, benzo[ b]thiophene, and benzo[ b]selenophene is presented. The key transformations utilized in the described syntheses include Sonogashira couplings, Cacchi and alkyne electrophilic cyclizations, Horner-Wadsworth-Emmons (HWE) reaction, chemoselective Suzuki-Miyaura couplings, and acid-promoted intramolecular cyclization to form the seven-membered ring of (±)-dehydroampelopsin B.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Natural Sciences Organic Chemistry
Identifiers
urn:nbn:se:umu:diva-153480 (URN)10.1021/acs.orglett.8b02638 (DOI)000449443100009 ()30350667 (PubMedID)
Funder
Swedish Research Council, 621-2014-4670
Available from: 2018-11-21 Created: 2018-11-21 Last updated: 2018-11-27Bibliographically approved
Saleeb, M. (2018). Towards novel antibacterials: Synthesis and identification of natural product inspired inhibitors of Chlamydia trachomatis and development of chemical probes targeting virulence of Pseudomonas aeruginosa. (Doctoral dissertation). Umeå: Umeå University
Open this publication in new window or tab >>Towards novel antibacterials: Synthesis and identification of natural product inspired inhibitors of Chlamydia trachomatis and development of chemical probes targeting virulence of Pseudomonas aeruginosa
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Antibiotic resistance has evolved significantly to become one of the serious threats to public health today. Yet, the pipeline of new antibiotics is drying up and is lagging behind the challenging needs. As a contribution to this recurrent need for novel antibacterials, we applied multidisciplinary strategies to identify small-molecule antibacterials against Chlamydia trachomatis and antivirulence agents against Pseudomonas aeruginosa infections. These strategies included:

1. Synthesis of a focused compounds library inspired by natural product scaffolds followed by phenotypic screening against Chlamydia trachomatis. (Paper I)

(-)-Hopeaphenol is a polyphenol natural product that was identified as an antivirulence agent against Y. pseudotuberculosis and P. aeruginosa. Hopeaphenol core scaffold, 2,3-diaryl-2,3-dihydrobenzofuran, is ubiquitous in polyphenolic phytochemicals. In this thesis, a focused library of forty-eight compounds was synthesized based on 2,3-diarylbenzofuran and 2,3-diaryl-2,3- dihydrobenzofuran. The library was then explored for antibacterial properties in a number of screening assays and resulted in five novel antichlamydial compounds with inhibition potency down to sub-micromolar. The identified molecules also inhibited the growth of different clinical presentations of C. trachomatis, one of the most common sexually transmitted disease worldwide.

2. Target-based screening against the P. aeruginosa virulence factor using enzymatic and biophysical assays. (Paper II-IV)

P. aeruginosa is a Gram-negative opportunistic pathogen with remarkable antibiotic resistance that is associated with a wide range of clinical infections. An alternative strategy to develop novel and selective antibacterials is to target the bacterial virulence factors, i.e. the ability of the bacteria to promote disease, thus ‘disarming’ the pathogens instead of killing them. P. aeruginosa employs its virulence factor, the type III secretion system (T3SS), to inject toxins (e.g. ExoS) into the eukaryotic cytosol. In one part of this thesis, we utilized enzymatic assay and identified inhibitors against the P. aeruginosa T3S toxin (ExoS). A follow up structure-activity relationship analysis was established and resulted in five (low micromolar) inhibitors of ExoS ADP-ribosylation enzymatic activity. In another part, we used surface plasmon resonance biophysical assay and identified small molecule binders of T3S translocation protein (PcrV). The primary SAR analysis was established and showed the antivirulence properties of these molecules and the potential to expand them further as novel antibacterials.

Place, publisher, year, edition, pages
Umeå: Umeå University, 2018. p. 95
Keywords
Antibacterials, antibiotics, small molecules, natural products, benzofuran, dihydrobenzofuran, the type III secretion system, Pseudomonas aeruginosa, Chlamydia trachomatis, phenotypic screening, high-throughput screening, surface plasmon resonance, drug discovery, bacterial toxins, enzyme inhibitors
National Category
Natural Sciences Organic Chemistry
Research subject
Organic Chemistry
Identifiers
urn:nbn:se:umu:diva-150970 (URN)978-91-7601-917-7 (ISBN)
Public defence
2018-09-14, KB.E3.03 (Stora hörsalen), KBC-huset, Umeå, 09:00 (English)
Opponent
Supervisors
Funder
Swedish Foundation for Strategic Research , SSF, SB12-0022
Available from: 2018-08-24 Created: 2018-08-21 Last updated: 2018-08-21Bibliographically approved
Pinto, A. F., Ebrahimi, M., Saleeb, M., Forsberg, Å., Elofsson, M. & Schüler, H. (2016). Identification of Inhibitors of Pseudomonas aeruginosa Exotoxin-S ADP-Ribosyltransferase Activity. Journal of Biomolecular Screening, 21(6), 590-595
Open this publication in new window or tab >>Identification of Inhibitors of Pseudomonas aeruginosa Exotoxin-S ADP-Ribosyltransferase Activity
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2016 (English)In: Journal of Biomolecular Screening, ISSN 1087-0571, E-ISSN 1552-454X, Vol. 21, no 6, p. 590-595Article in journal (Refereed) Published
Abstract [en]

The gram-negative bacterium Pseudomonas aeruginosa is an opportunistic pathogen associated with drug resistance complications and, as such, an important object for drug discovery efforts. One attractive target for development of therapeutics is the ADP-ribosyltransferase Exotoxin-S (ExoS), an early effector of the type III secretion system that is delivered into host cells to affect their transcription pattern and cytoskeletal dynamics. The purpose of this study was to formulate a real-time assay of purified recombinant ExoS activity for high-throughput application. We characterized the turnover kinetics of the fluorescent dinucleotide 1,N-6-etheno-NAD+ as co-substrate for ExoS. Further, we found that the toxin relied on any of five tested isoforms of human 14-3-3 to modify vH-Ras and the Rho-family GTPases Rac1, -2, and -3 and RhoC. We then used 14-3-3-stimulated ExoS modification of vH-Ras to screen a collection of low-molecular-weight compounds selected to target the poly-ADP ribose polymerase family and identified 3-(4-oxo-3,5,6,7-tetrahydro-4H-cyclopenta[4,5]thieno[2,3-d]pyrimidin-2-y l)propanoic acid as an ExoS inhibitor with micromolar potency. Thus, we present an optimized method to screen for inhibitors of ExoS activity that is amenable to high-throughput format and an intermediate affinity inhibitor that can serve both as assay control and as a starting point for further development.

Keywords
ADP-ribosylation, bacterial toxins, drug discovery, enzyme inhibitors, Pseudomonas aeruginosa
National Category
Biochemistry and Molecular Biology Medicinal Chemistry
Identifiers
urn:nbn:se:umu:diva-124333 (URN)10.1177/1087057116629923 (DOI)000379694900007 ()26850638 (PubMedID)
Available from: 2016-09-22 Created: 2016-08-04 Last updated: 2018-08-24Bibliographically approved
Caraballo, R., Saleeb, M., Bauer, J., Liaci, A.-M., Chandra, N., Storm, R. J., . . . Elofsson, M. (2015). Triazole linker-based trivalent sialic acid inhibitors of adenovirus type 37 infection of human corneal epithelial cells. Organic and biomolecular chemistry, 13(35), 9194-9205
Open this publication in new window or tab >>Triazole linker-based trivalent sialic acid inhibitors of adenovirus type 37 infection of human corneal epithelial cells
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2015 (English)In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 13, no 35, p. 9194-9205Article in journal (Refereed) Published
Abstract [en]

Adenovirus type 37 (Ad37) is one of the principal agents responsible for epidemic keratoconjunctivitis (EKC), a severe ocular infection that remains without any available treatment. Recently, a trivalent sialic acid derivative (ME0322, Angew. Chem. Int. Ed., 2011, 50, 6519) was shown to function as a highly potent inhibitor of Ad37, efficiently preventing the attachment of the virion to the host cells and subsequent infection. Here, new trivalent sialic acid derivatives were designed, synthesized and their inhibitory properties against Ad37 infection of the human corneal epithelial cells were investigated. In comparison to ME0322, the best compound (17a) was found to be over three orders of magnitude more potent in a cell-attachment assay (IC50 = 1.4 nM) and about 140 times more potent in a cell-infection assay (IC50 = 2.9nM). X-ray crystallographic analysis demonstrated a trivalent binding mode of all compounds to the Ad37 fiber knob. For the most potent compound ophthalmic toxicity in rabbits was investigated and it was concluded that repeated eye administration did not cause any adverse effects.

National Category
Microbiology in the medical area
Identifiers
urn:nbn:se:umu:diva-100014 (URN)10.1039/C5OB01025J (DOI)000360115100007 ()
Available from: 2015-02-18 Created: 2015-02-18 Last updated: 2019-08-28Bibliographically approved
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