scholarly journals Anti-tuberculosis Compound Screen using a Zebrafish Infection Model identifies an Aspartyl-tRNA Synthetase Inhibitor

2021 ◽  
Author(s):  
Eva Habjan ◽  
Vien Q. T. Ho ◽  
James Gallant ◽  
Gunny Van Stempvoort ◽  
Kin Ki Jim ◽  
...  
Keyword(s):  
Zebrafish Embryo ◽  
Point Mutations ◽  
Docking Studies ◽  
Trna Synthetase ◽  
Infection Model ◽  
Active Compounds ◽  
Global Challenge ◽  
Highly Active ◽  
Zebrafish Infection

Finding new anti-tuberculosis compounds with convincing in vivo activity is an ongoing global challenge to fight the emergence of multi-drug resistant Mycobacterium tuberculosis isolates. In this work, we exploited the medium-throughput capabilities of the zebrafish embryo infection model with Mycobacterium marinum as a surrogate for M. tuberculosis. Using a representative set of clinically established drugs, we demonstrate that this model could be predictive and selective for antibiotics that can be administered orally. We further used the zebrafish-infection model to screen 240 compounds from an anti-TB hit library for their in vivo activity and identified 14 highly active compounds. One of the most active compounds was the tetracyclic compound TBA161, which was studied in more detail. Analysis of resistant mutants revealed point mutations in aspS (rv2572c), encoding an aspartyl-tRNA synthetase. The target was genetically confirmed, and molecular docking studies propose possible binding of TBA161 in a pocket adjacent to the catalytic site. This study showed that the zebrafish-infection model is suitable to rapidly identify promising scaffolds with in vivo activity.

scholarly journals Methionyl-tRNA synthetase inhibitor has potent in vivo activity in a novel Giardia lamblia luciferase murine infection model

2020 ◽  
Vol 75 (5) ◽  
pp. 1218-1227
Author(s):  
Samantha A Michaels ◽  
Han-Wei Shih ◽  
Bailin Zhang ◽  
Edelmar D Navaluna ◽  
Zhongsheng Zhang ◽  
...  
Keyword(s):  
Giardia Lamblia ◽  
Trna Synthetase ◽  
Luciferase Reporter ◽  
Infection Model ◽  
Cell Assay ◽  
Mouse Infection Model ◽  
Mouse Infection ◽  
Methionyl Trna Synthetase

Abstract Background Methionyl-tRNA synthetase (MetRS) inhibitors are under investigation for the treatment of intestinal infections caused by Giardia lamblia. Objectives To properly analyse the therapeutic potential of the MetRS inhibitor 1717, experimental tools including a robust cell-based assay and a murine model of infection were developed based on novel strains of G. lamblia that employ luciferase reporter systems to quantify viable parasites. Methods Systematic screening of Giardia-specific promoters and luciferase variants led to the development of a strain expressing the click beetle green luciferase. Further modifying this strain to express NanoLuc created a dual reporter strain capable of quantifying parasites in both the trophozoite and cyst stages. These strains were used to develop a high-throughput cell assay and a mouse infection model. A library of MetRS inhibitors was screened in the cell assay and Compound-1717 was tested for efficacy in the mouse infection model. Results Cell viability in in vitro compound screens was quantified via bioluminescence readouts while infection loads in mice were monitored with non-invasive whole-animal imaging and faecal analysis. Compound-1717 was effective in clearing mice of Giardia infection in 3 days at varying doses, which was supported by data from enzymatic and phenotypic cell assays. Conclusions The new in vitro and in vivo assays based on luciferase expression by engineered G. lamblia strains are useful for the discovery and development of new therapeutics for giardiasis. MetRS inhibitors, as validated by Compound-1717, have promising anti-giardiasis properties that merit further study as alternative therapeutics.

scholarly journals The antiseptic and trypanocidal action of certain styryl and anil quinoline carboxylamides.*

1932 ◽  
Vol 110 (767) ◽  
pp. 249-260
Keyword(s):  
Amide Group ◽  
The Other ◽  
Amino Group ◽  
Active Compounds ◽  
Basic Group ◽  
Urethane Group ◽  
Highly Active ◽  
Quaternary Compounds ◽  
Quinoline Series

In the case of quaternary compounds of the styryl quinoline series and of the analogous benzthiazole derivatives a powerful trypanocidal effect in vivo has been shown to depend on the presence in the substance of a free basic group in one of the nuclei, and anacylamino (especially acetyl) or urethane group in the other, and also on the styryl linkage—each playing a definite part in contributing to the action (Browning, Cohen, Ellingworth and Gulbransen, 1929, 1931). This is exemplified by 2( p -aminostyryl)-6 acetylamino quinoline methochloride (No. 8), 2( p -dimethylamino styryl)-6 acetylamino quinoline methochloride (No. 25), 2( p -acetylamino)-6 dimethylamino quinoline methochloride (No. 90) and 2( p -dimethylamino styryl) quinolyl (6) urethane (Me) methochloride (No. 125). The effect of acetylation of the amino group parallels that dis­covered by Ehrlich and his co-workers in the case of p -amino phenyl arsinic acid. Gough and King (1930) have recently made the important observation that in the latter series the introduction of an amide group converts the therapeutically inactive carboxylic and sulphonic acids into active compounds. Accordingly, the effect of substituting a carboxylamide group for the acylamino in compounds of the type of No. 25 and its anil analogue (No. 62) has been investigated. In addition, the position of the carboxylamide group has been varied. These substances were further examined for antiseptic action, the results being shown in the table. Trypanocidal properties have been tested on T. brucei infections in mice as in previous work. The striking observation has been made that only those compounds with the carboxylamide group in the 6 position are therapeutically active, the anils being only slightly less effective than the styryl analogues ( cf . Nos. 410, 409 and 385, 403). This contrasts with what is found in the acetylamino derivatives, since the styryl compounds of the latter are highly active as compared with the corresponding anils. The carboxy-ethylamides (420, 419) are more toxic and less trypanocidal than the corresponding amides and methylamides.

scholarly journals Zebrafish Embryo Model for Assessment of Drug Efficacy on Mycobacterial Persisters

2020 ◽  
Vol 64 (10) ◽  
Author(s):  
Susanna Commandeur ◽  
Nino Iakobachvili ◽  
Marion Sparrius ◽  
Mariam Mohamed Nur ◽  
Galina V. Mukamolova ◽  
...  
Keyword(s):  
Drug Screening ◽  
Zebrafish Embryo ◽  
Neutral Lipids ◽  
Drug Efficacy ◽  
Infection Model ◽  
Duration Of Treatment ◽  
Content Type ◽  
Set Up

ABSTRACT Tuberculosis continues to kill millions of people each year. The main difficulty in eradication of the disease is the prolonged duration of treatment, which takes at least 6 months. Persister cells have long been associated with failed treatment and disease relapse because of their phenotypical, though transient, tolerance to drugs. By targeting these persisters, the duration of treatment could be shortened, leading to improved tuberculosis treatment and a reduction in transmission. The unique in vivo environment drives the generation of persisters; however, appropriate in vivo mycobacterial persister models enabling optimized drug screening are lacking. To set up a persister infection model that is suitable for this, we infected zebrafish embryos with in vitro-starved Mycobacterium marinum. In vitro starvation resulted in a persister-like phenotype with the accumulation of stored neutral lipids and concomitant increased tolerance to ethambutol. However, these starved wild-type M. marinum organisms rapidly lost their persister phenotype in vivo. To prolong the persister phenotype in vivo, we subsequently generated and analyzed mutants lacking functional resuscitation-promoting factors (Rpfs). Interestingly, the ΔrpfAB mutant, lacking two Rpfs, established an infection in vivo, whereas a nutrient-starved ΔrpfAB mutant did maintain its persister phenotype in vivo. This mutant was, after nutrient starvation, also tolerant to ethambutol treatment in vivo, as would be expected for persisters. We propose that this zebrafish embryo model with ΔrpfAB mutant bacteria is a valuable addition for drug screening purposes and specifically screens to target mycobacterial persisters.

scholarly journals A preliminary study of in vitro and in vivo synergistic effects of ciprofloxacin and D-tyrosine against Pseudomonas aeruginosa isolates

2020 ◽  
Vol 19 (8) ◽  
pp. 1731-1736
Author(s):  
Huirong Li ◽  
Wei Jiang ◽  
Xiaoshuang He ◽  
Mengting Chen
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Synergistic Effects ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Infection Model ◽  
Antimicrobial Effects ◽  
Kill Curve ◽  
Zebrafish Infection

Purpose: To investigate the synergistic antimicrobial effects of ciprofloxacin and D-tyrosine against drug-resistant bacteria.Method: The antimicrobial effects of ciprofloxacin and D-tyrosine on clinical isolates of multidrugresistant (MDR) Pseudomonas aeruginosa (P. aeruginosa) no. 3556 were determined in vitro based on time-kill curve, and in vivo in P. aeruginosa-zebrafish infection model. Furthermore, 30 clinical isolates of multidrug-resistant P. aeruginosa were used in vitro to ascertain the synergistic effect of the two agents.Results: Combined use of ciprofloxacin and D-tyrosine produced synergistic effects against the clinical isolate of P. aeruginosa no. 3556 in vitro and in vivo. Synergism occurred in 96.67 % (95 % CI, range 83.33 - 99.41 %) of the clinical isolates, and ciprofloxacin dose was reduced in 90 % (95 % CI, range 74.38 - 96.54 %) of the clinical isolates in vitro.Conclusion: These preliminary results suggest that the combination of ciprofloxacin and D-tyrosine is a promising therapeutic strategy against MDR P. aeruginosa infections. Keywords: Ciprofloxacin, D-tyrosine, Synergistic, P. aeruginosa, Zebrafish infection model, Time-killing curve

scholarly journals Zebrafish Embryo Infection Model to Investigate Pseudomonas aeruginosa Interaction With Innate Immunity and Validate New Therapeutics

2021 ◽  
Vol 11 ◽  
Author(s):  
Stéphane Pont ◽  
Anne-Béatrice Blanc-Potard
Keyword(s):  
Immune Response ◽  
Pseudomonas Aeruginosa ◽  
Innate Immunity ◽  
Innate Immune Response ◽  
Zebrafish Embryo ◽  
Acquired Resistance ◽  
Innate Immune ◽  
Infection Model ◽  
Opportunistic Human Pathogen

The opportunistic human pathogen Pseudomonas aeruginosa is responsible for a variety of acute infections and is a major cause of mortality in chronically infected patients with cystic fibrosis (CF). Considering the intrinsic and acquired resistance of P. aeruginosa to currently used antibiotics, new therapeutic strategies against this pathogen are urgently needed. Whereas virulence factors of P. aeruginosa are well characterized, the interplay between P. aeruginosa and the innate immune response during infection remains unclear. Zebrafish embryo is now firmly established as a potent vertebrate model for the study of infectious human diseases, due to strong similarities of its innate immune system with that of humans and the unprecedented possibilities of non-invasive real-time imaging. This model has been successfully developed to investigate the contribution of bacterial and host factors involved in P. aeruginosa pathogenesis, as well as rapidly assess the efficacy of anti-Pseudomonas molecules. Importantly, zebrafish embryo appears as the state-of-the-art model to address in vivo the contribution of innate immunity in the outcome of P. aeruginosa infection. Of interest, is the finding that the zebrafish encodes a CFTR channel closely related to human CFTR, which allowed to develop a model to address P. aeruginosa pathogenesis, innate immune response, and treatment evaluation in a CF context.

scholarly journals The Resistance to Host Antimicrobial Peptides in Infections Caused by Daptomycin-Resistant Staphylococcus aureus

Antibiotics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 96
Author(s):  
Md Saruar Bhuiyan ◽  
Jhih-Hang Jiang ◽  
Xenia Kostoulias ◽  
Ravali Theegala ◽  
Graham J. Lieschke ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Immune Responses ◽  
Antimicrobial Peptides ◽  
Innate Immune ◽  
Cross Resistance ◽  
Infection Model ◽  
Innate Immune Responses ◽  
Persistent Infections ◽  
Zebrafish Infection

Daptomycin is an important antibiotic for the treatment of infections caused by Staphylococcus aureus. The emergence of daptomycin resistance in S. aureus is associated with treatment failure and persistent infections with poor clinical outcomes. Here, we investigated host innate immune responses against clinically derived, daptomycin-resistant (DAP-R) and -susceptible S. aureus paired isolates using a zebrafish infection model. We showed that the control of DAP-R S. aureus infections was attenuated in vivo due to cross-resistance to host cationic antimicrobial peptides. These data provide mechanistic understanding into persistent infections caused by DAP-R S. aureus and provide crucial insights into the adaptive evolution of this troublesome pathogen.

scholarly journals Antibacterial Activity and Molecular Docking Studies of a Selected Series of Hydroxy-3-arylcoumarins

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2815 ◽  
Author(s):  
Pisano ◽  
Kumar ◽  
Medda ◽  
Gatto ◽  
Pal ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Molecular Docking ◽  
Structural Features ◽  
Docking Studies ◽  
Trna Synthetase ◽  
Hydroxyl Groups ◽  
Bacterial Strains ◽  
Active Compounds ◽  
Molecular Docking Studies

Antibiotic resistance is one of the main public health concerns of this century. This resistance is also associated with oxidative stress, which could contribute to the selection of resistant bacterial strains. Bearing this in mind, and considering that flavonoid compounds are well known for displaying both activities, we investigated a series of hydroxy-3-arylcoumarins with structural features of flavonoids for their antibacterial activity against different bacterial strains. Active compounds showed selectivity against the studied Gram-positive bacteria compared to Gram-negative bacteria. 5,7-Dihydroxy-3-phenylcoumarin (compound 8) displayed the best antibacterial activity against Staphylococcus aureus and Bacillus cereus with minimum inhibitory concentrations (MICs) of 11 g/mL, followed by Staphylococcus aureus (MRSA strain) and Listeria monocytogenes with MICs of 22 and 44 g/mL, respectively. Moreover, molecular docking studies performed on the most active compounds against Staphylococcus aureus tyrosyl-tRNA synthetase and topoisomerase II DNA gyrase revealed the potential binding mode of the ligands to the site of the appropriate targets. Preliminary structure–activity relationship studies showed that the antibacterial activity can be modulated by the presence of the 3-phenyl ring and by the position of the hydroxyl groups at the coumarin scaffold.

scholarly journals In Vitro Selection and In Vivo Efficacy of Piperazine- and Alkanediamide-Linked Bisbenzamidines against Pneumocystis Pneumonia in Mice

2006 ◽  
Vol 50 (7) ◽  
pp. 2337-2343 ◽  
Author(s):  
Melanie T. Cushion ◽  
Peter D. Walzer ◽  
Alan Ashbaugh ◽  
Sandra Rebholz ◽  
Ronald Brubaker ◽  
...  
Keyword(s):  
Mouse Model ◽  
In Vitro Selection ◽  
Parent Compound ◽  
Pneumocystis Pneumonia ◽  
In Vitro Cytotoxicity ◽  
Active Compounds ◽  
Cytotoxicity Assays ◽  
Highly Active

ABSTRACT Bisbenzamidines, such as pentamidine isethionate, are aromatic dicationic compounds that are active against Pneumocystis and other microbes but are oftentimes toxic to the host. To identify potential anti-Pneumocystis agents, we synthesized bisbenzamidine derivatives in which the parent compound pentamidine was modified by a 1,4-piperazinediyl, alkanediamide, or 1,3-phenylenediamide moiety as the central linker. Several of the compounds were more active against P. carinii and less toxic than pentamidine in cytotoxicity assays. For this study, we evaluated nine bisbenzamidine derivatives representing a range of in vitro activities, from highly active to inactive, for the treatment of pneumocystosis in an immunosuppressed mouse model. Six of these in vitro-active compounds, 01, 02, 04, 06, 100, and 101, exhibited marked efficacies against infection at a dose of 10 mg/kg of body weight, and four compounds, 01, 04, 100, and 101, showed significant increases in survival versus that of untreated infected control mice. Compound 100 was highly efficacious against the infection at 20 mg/kg and 40 mg/kg, with >1,000-fold reductions in burden, and resulted in improved survival curves versus those for pentamidine-treated mice (at the same doses). All six bisbenzamidine compounds that exhibited high in vitro activity significantly decreased the infection in vivo; two compounds, 12 and 102, with marked to moderate in vitro activities had slight or no activity in vivo, while compound 31 was inactive in vitro and was also inactive in vivo. Thus, the selection of highly active compounds from in vitro cytotoxicity assays was predictive of activity in the mouse model of Pneumocystis pneumonia. We conclude that a number of these bisbenzamidine compounds, especially compound 100, may show promise as new anti-Pneumocystis drugs.

scholarly journals Semisynthetic glycopeptide antibiotics derived from LY264826 active against vancomycin-resistant enterococci.

1996 ◽  
Vol 40 (9) ◽  
pp. 2194-2199 ◽  
Author(s):  
T I Nicas ◽  
D L Mullen ◽  
J E Flokowitsch ◽  
D A Preston ◽  
N J Snyder ◽  
...  
Keyword(s):  
In Vivo Studies ◽  
Infection Model ◽  
Glycopeptide Antibiotics ◽  
Coagulase Negative Staphylococci ◽  
Antibiotic Resistant ◽  
Methicillin Resistant ◽  
Mouse Infection Model ◽  
Highly Active ◽  
Vancomycin Resistant

Certain derivatives of the glycopeptide antibiotic LY264826 with N-alkyl-linked substitutions on the epivancosamine sugar are active against glycopeptide-resistant enterococci. Six compounds representing our most active series were evaluated for activity against antibiotic-resistant, gram-positive pathogens. For Enterococcus faecium and E. faecalis resistant to both vancomycin and teicoplanin, the MICs of the six semisynthetic compounds for 90% of the strains tested were 1 to 4 micrograms/ml, compared with 2,048 micrograms/ml for vancomycin and 256 micrograms/ml for LY264826. For E. faecium and E. faecalis resistant to vancomycin but not teicoplanin, the MICs were 0.016 to 1 micrograms/ml, compared with 64 to 1,024 micrograms/ml for vancomycin. The compounds were highly active against vancomycin-susceptible enterococci and against E. gallinarum and E. casseliflavus and showed some activity against isolates of highly vancomycin-resistant leuconostocs and pediococci. The MICs for 90% of the strains of methicillin-resistant Staphylococcus aureus tested were typically 0.25 to 1 micrograms/ml, compared with 1 microgram/ml for vancomycin. Against methicillin-resistant S. epidermidis MICs ranged from 0.25 to 2 micrograms/ml, compared with 1 to 4 micrograms/ml for vancomycin and 4 to 16 micrograms/ml for teicoplanin. The spectrum of these new compounds included activity against teicoplanin-resistant, coagulase-negative staphylococci. The compounds exhibited exceptional potency against pathogenic streptococci, with MICs of < or = 0.008 microgram/ml against Streptococcus pneumoniae, including penicillin-resistant isolates. In in vivo studies with a mouse infection model, the median effective doses against a challenge by S. aureus, S. pneumoniae, or S. pyogenes were typically 4 to 20 times lower than those of vancomycin. Overall, these new glycopeptides, such as LY307599 and LY333328, show promise for use as agents against resistant enterococci, methicillin-resistant S. aureus, and penicillin-resistant pneumococci.

scholarly journals Methionyl-tRNA synthetase inhibitor has potent in vivo activity in a novel Giardia lamblia luciferase murine infection model

2019 ◽  
Author(s):  
Samantha A. Michaels ◽  
Han-Wei Shih ◽  
Bailin Zhang ◽  
Edelmar D. Navaluna ◽  
Zhongsheng Zhang ◽  
...  
Keyword(s):  
Giardia Lamblia ◽  
Trna Synthetase ◽  
Luciferase Reporter ◽  
Infection Model ◽  
Cell Assay ◽  
Mouse Infection Model ◽  
Mouse Infection ◽  
Methionyl Trna Synthetase

AbstractObjectivesMethionyl-tRNA synthetase (MetRS) inhibitors are under investigation for the treatment of intestinal infections caused by Giardia lamblia. To properly analyze the therapeutic potential of the MetRS inhibitor 1717, experimental tools including a robust cell-based assay and a murine model of infection were developed based on novel strains of G. lamblia that employ luciferase reporter systems to quantify viable parasites.MethodsSystematic screening of Giardia-specific promoters and luciferase variants led to the development of a strain expressing the click beetle green luciferase. Further modifying this strain to express NanoLuc created a dual reporter strain capable of quantifying parasites in both the trophozoite and cyst stages. These strains were used to develop a high throughput cell assay and a mouse infection model. A library of MetRS inhibitors was screened in the cell assay and 1717 was tested for efficacy in the mouse infection model.ResultsCell viability in in vitro compound screens was quantified via bioluminescence readouts while infection loads in mice were monitored with noninvasive whole-animal imaging and fecal analysis. Compound 1717 was effective in clearing mice of Giardia infection in 3 days at varying doses, which is supported by data from enzymatic and phenotypic cell assays.ConclusionsThe new in vitro and in vivo assays based on luciferase expression by engineered G. lamblia strains are useful for the discovery and development of new therapeutics for giardiasis. MetRS inhibitors, as validated by 1717, have promising anti-giardiasis properties that merit further study as alternative therapeutics.

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