Publications by authors named "Buckner F"

New antibiotics are needed to treat gram-positive bacterial pathogens. is a novel inhibitor of methionyl-tRNA synthetase with selective activity against gram-positive bacteria. The minimum inhibitory concentrations (MICs) against and species range from 0.

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  • Leishmaniasis is a rare but underreported disease in the U.S., primarily affecting travelers and migrants, with an annual incidence of only a few dozen cases, making true rates difficult to ascertain.
  • From September 2021 to August 2022, a national reference laboratory tested 218 specimens, identifying 50.5% as positive, mostly linked to subgenus species causing cutaneous or mucocutaneous diseases.
  • The study underscores the need for improved molecular testing and reveals a higher-than-reported incidence of mucosal leishmaniasis and greater genetic diversity within species found in the Americas.
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Cutaneous leishmaniasis (CL) is often caused by Leishmania braziliensis (L. braziliensis) in South America. Because of the risk for mucocutaneous leishmaniasis, L.

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  • The article discusses two projects aimed at creating drugs for tropical diseases like Malaria, African sleeping sickness, and Chagas disease, primarily based in a University environment.
  • It highlights the collaboration with pharmaceutical companies to transition from initial drug discovery to clinical trial readiness.
  • The two specific cases examined are the development of inhibitors for protein farnesyltransferase and a group of compounds called benzthiazoles, which are under investigation for their effectiveness.
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The intestinal protozoan is a leading cause of diarrheal disease and mortality in young children. There is currently no fully effective treatment for cryptosporidiosis, which has stimulated interest in anticryptosporidial development over the last ∼10 years, with numerous lead compounds identified, including several tRNA synthetase inhibitors. Here, we report the results of a dairy calf efficacy trial of the methionyl-tRNA ( MetRS [MetRS]) synthetase inhibitor 2093 and the spontaneous emergence of drug resistance.

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  • Researchers developed two groups of new inhibitors for the enzyme methionyl-tRNA synthetase (MetRS) found in parasites, utilizing different chemical linkers in their design.
  • Both groups of inhibitors were effective at low concentrations (EC < 10 nM) in stopping parasite growth, while showing minimal toxicity to human cells (CCs > 20,000 nM).
  • Despite their effectiveness, the inhibitors had limited ability to cross the blood-brain barrier, indicating that further modifications are needed for treatment in advanced cases of human African trypanosomiasis.
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Neglected tropical diseases remain among the most critical public health concerns in Africa and South America. The drug treatments for these diseases are limited, which invariably leads to fatal cases. Hence, there is an urgent need for new antitrypanosomal drugs.

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Background: Washington State served as the initial epicenter of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in the United States. An understanding of the risk factors and clinical outcomes of hospitalized patients with coronavirus disease 2019 (COVID-19) may provide guidance for management.

Methods: All laboratory-confirmed COVID-19 cases in adults admitted to an academic medical center in Seattle, Washington, between 2 March and 26 March 2020 were included.

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The work began with the screening of a library of 700,000 small molecules for inhibitors of growth (a phenotypic screen). The resulting set of 1035 hit compounds was reviewed by a team of medicinal chemists, leading to the nomination of 17 chemically distinct scaffolds for further investigation. The first triage step was the assessment for brain permeability (looking for brain levels at least 20% of plasma levels) in order to optimize the chances of developing candidates for treating late-stage human African trypanosomiasis.

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  • Methionyl-tRNA synthetase (MetRS) inhibitors are being researched for treating intestinal infections caused by the parasite Giardia lamblia, with Compound-1717 showing potential efficacy.
  • Researchers developed a cell-based assay and a murine (mouse) model using engineered G. lamblia strains that express luciferase, allowing for effective quantification of the parasite in different life stages.
  • The study demonstrated that Compound-1717 successfully cleared Giardia infection in mice within 3 days, indicating that MetRS inhibitors could be a promising avenue for developing new treatments for giardiasis.
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  • Mycobacterium avium complex (MAC) infections are typically seen as opportunistic, raising concerns about underlying immune system issues.
  • These infections can also affect patients who otherwise have a normal immune response, especially those with structural lung problems.
  • The case presented involves a patient with low T-cell levels (lymphopenia) complicating their pulmonary MAC infection, despite being negative for HIV.
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  • In May 2019, an international conference organized by the Wellcome Centre for Anti-Infectives Research at the University of Dundee focused on finding new medicines to treat infectious diseases, especially in Low and Middle Income Countries.
  • The conference highlighted the urgent need for new drugs and aimed to learn from various disease areas to improve drug discovery and development processes.
  • The discussions included topics from clinical development back to drug discovery pathways, emphasizing the importance of collaboration between preclinical and clinical phases.
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Pyridyl benzamide 2 is a potent inhibitor of Trypanosoma cruzi, but not other protozoan parasites, and had a selectivity-index of ≥10. The initial structure-activity relationship (SAR) indicates that benzamide and sulfonamide functional groups, and N-methylpiperazine and sterically unhindered 3-pyridyl substructures are required for high activity against T. cruzi.

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The protozoan parasite can induce amebic colitis and amebic liver abscess. First-line drugs for the treatment of amebiasis are nitroimidazoles, particularly metronidazole. Metronidazole has side effects and potential drug resistance is a concern.

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Cryptosporidiosis is one of the leading causes of moderate to severe diarrhea in children in low-resource settings. The therapeutic options for cryptosporidiosis are limited to one drug, nitazoxanide, which unfortunately has poor activity in the most needy populations of malnourished children and HIV-infected persons. We describe here the discovery and early optimization of a class of imidazopyridine-containing compounds with potential for treating infections.

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Better therapeutics are greatly needed to treat patients infected with trypanosomatid parasites such as or . This report describes 28 new imidazopyridines and triazolopyrimidines with potent and selective antitrypanosomal activity. Drug-like properties were demonstrated in a number of in vitro assays.

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  • Mycobacterium tuberculosis causes about 1.5 million deaths each year, and current treatments involve long-term medication with serious side effects, leading to drug resistance.
  • Researchers have revealed the crystal structure of the methionyl-tRNA synthetase (MetRS) from M. tuberculosis, identifying key differences in the enzyme's active site compared to human enzymes.
  • These differences suggest the potential for developing selective inhibitors that can target the bacterial enzyme more effectively without impacting human enzymes, which is crucial for new treatment options.
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Antibiotic-resistant bacteria are widespread and pose a growing threat to human health. New antibiotics acting by novel mechanisms of action are needed to address this challenge. The bacterial methionyl-tRNA synthetase (MetRS) enzyme is essential for protein synthesis, and the type found in Gram-positive bacteria is substantially different from its counterpart found in the mammalian cytoplasm.

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A high throughput screening and subsequent hit validation identified compound as an inhibitor of parasite growth. Extensive structure-activity relationship optimization based on antiparasitic activity led to the highly potent compounds, 1-(4-fluorobenzyl)-3-(4-dimethylamino-3-chlorophenyl)-2-thiohydantoin () and 1-(2-chloro-4-fluorobenzyl)-3-(4-dimethylamino-3-methoxyphenyl)-2-thiohydantoin (), with a EC of 3 and 2 nM, respectively. This represents >100-fold improvement in potency compared to compound .

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  • * Of these compounds, 7 and 12 showed effective in vitro activity against different parasites with an EC of ≤ 1 μM, and one compound was chosen for further testing due to its favorable properties.
  • * In an acute mouse study, this selected compound showed promising results, inhibiting parasites similarly to the established treatment drug, benznidazole, indicating its potential as a new drug for treating trypanosomiasis.
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  • To enhance the effectiveness of these inhibitors, researchers investigated a binding fragment that targets a specific region known as the "enlarged methionine pocket" (EMP).
  • This led to the discovery of a 6,8-dichloro-tetrahydroquinoline ring, which when substituted into compound 2 resulted in a new compound, 13, showing a remarkable potency with an EC of 4nM.
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  • The crystal structure of LdTyrRS (Leishmania donovani tyrosyl-tRNA synthetase) was determined at a resolution of 2.75 Å, revealing its complex with a nanobody and a tyrosyl adenylate analog.
  • The nanobody stabilizes LdTyrRS by reducing the flexibility of a specific loop and allows for crucial interactions with the enzyme's active site, which is necessary for tRNA charging.
  • An "extra pocket" (EP) near the adenine binding site presents a unique target for drug development to treat infections caused by L. donovani, potentially leading to therapies for various parasitic diseases due to similarities in other pathogenic protozoa.
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  • A screening of a compound library found a promising class of compounds, N-(2-aminoethyl)-N-phenyl benzamides, with potential against Trypanosoma brucei, the parasite causing Human African Trypanosomiasis.
  • Researchers synthesized 82 analogues and discovered that compound 73 was particularly effective, showing a low effective concentration (EC) of 0.001μM in vitro tests.
  • Compound 73 demonstrated good oral bioavailability and cured 2 out of 3 mice infected with the parasite when administered at a specific dosage, suggesting its potential use as a lead drug for treating the disease.
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